About Mepians

Mepians are a-life that inherited at least one body part from a nightmaren ancestor. These creatures are similar to nightopians in many ways, but have some important differences in their behavior. Unlike nightmarens and nightopians, which are naturally occurring, the player's involvement is required to create a mepian. Creating a mepian is described in more detail on the nightmarens page. In the overall a-life system, mepians have two main roles. 

One is to enable the creation of a king pian, which is the offspring of two mepians that happened to only inherit nightopian parts from each parent. 

The other is to outcompete the nightopian population and increase the likelihood of nightopians going extinct. A special type of mepian, known as a badpian by fans, has only nightmaren parts and is especially dangerous due to its ability to eat any a-life it touches, functioning similarly to full-blooded nightmarens.

Creating a King Pian

A king pian is basically a nightopian that had two mepians as parents. Every a-life randomly inherits each of its head, torso, arm, and leg parts from one of its two parents. Because of this, only certain pairings of mepians have a chance to make a king pian. If the two mepians have nightmaren parts on the same body part, such as both having nightmaren arms, there is no chance for them to make a king pian because their offspring will always inherit nightmaren arms. So, they need to have nightmaren parts in different places. The best chances come from two mepians that each have one, different nightmaren part. Take for instance one with a nightmaren head and one with a nightmaren torso, with all of their other body parts being from nightopians. 

If each body part has a 50% chance to pass down, the probability of inheriting nightopian parts works out like this:

Head part: 1/2 = 50%

Torso part: 1/2 = 50%

Arm part: 2/2 = 100%

Leg part 2/2 = 100%

To get the probability of an offspring with all nightopian parts, multiply all of these fractions together. That's (1*1*2*2)/(2*2*2*2)= 1/4. So in theory, there is on average a 25% chance for this pairing to produce a king pian offspring. Things are complicated a bit by the dominance system that causes the probability not to be 50% most of the time. In these cases, the probabilities might stack up to less or more than 25%, and in unfortunate cases due to a bug, the chance between two particular mepians may be 0% even if they have the right body parts. These unpredictable probabilities, added to the fact that the player has little influence over which mepians mate with each other, makes king pians exceedingly rare. 

Unique Genetic Behaviors

All a-life can have two out of 24 possible genetic behaviors coded in their DNA. For the most part, these behaviors match between nightopians and mepians, but there are a few cases where they differ. 

Genetic behavior 15:

This behavior causes singing in nightopians, but crying in mepians. Notably, this does not exclude mepians from singing, or nightopians from crying, at least in theory. Mepians can still sing if they have behavior 1, and nightopians can cry if they have behavior 2, but the conditions for each are different from behavior 15. 

Behavior 1 activates with any of the three behavior triggers, that is, going off-screen, moving near another a-life, and touching another a-life. Behavior 2 only activates if an a-life moves near or touches one that is dying (although this is bugged and doesn't work in-game). Meanwhile, behavior 15 doesn't activate when going off screen, but does when an a-life moves near or touches any other a-life, dying or not. This means mepians can appear to cry for no reason simply by being in the proximity of another a-life, while nightopians with behavior 2 never cry in practice. Interestingly, behavior 15 is always one of the behavior alleles in nightmarens (the other is 0, sleeping), giving first generation mepians a 50% chance of having it.

Genetic behavior 18:

This behavior causes fishing for cake in nightopians, and waving a flag for mepians. In both cases, this behavior activates when the a-life goes off-screen. Unlike with singing and crying, these behaviors are exclusive to nightopians and mepians, respectively. There is technically another behavior that can cause waving a flag in nightopians, but it will never activate under normal conditions. Unfortunately, the fishing behavior is bugged and will not activate either.

Genetic behavior 19:

For some reason, this behavior causes a nightopian to hide in fear when going off-screen, encountering, or touching another a-life, even if no threat is present. Meanwhile, it causes mepians to float using an umbrella if they are in midair and go off-screen. Behavior 23 in Soft Museum can also cause hiding in fear in both nightopians and mepians, but there is no behavior that can cause nightopians to use an umbrella.

Genetic behavior 20:

This behavior causes nightopians to dance and mepians to blow bubbles. In both cases, the behavior is activated when going off-screen. Behavior 22 is also intended to cause dancing for both nightopians and mepians, but it cannot activate under normal conditions. The same is true for behavior 17 in Stick Canyon, which is intended to cause blowing bubbles but never activates.

Genetic behavior 21:

Intended to cause nightopians to wave a flag and mepians to judge the player's acrobat performance. However, the waving flag behavior will not activate under normal conditions. Mepians' behavior 21 only activates when the acrobat timer == 1 and judges the player's performance like this: If the player did 0, 1, or 2 tricks during acrobat time, the mepian's mood lowers by 1, capped at 0. If the player did 3 or 4 tricks, its mood remains the same. If the player did 5 or more tricks, the mepian's mood rises to 3 (the max).

Unique Sounds

Mepians' singing sound and death sound differs from that of nightopians. nightopians sing three short notes from Dreams Dreams' leitmotif, while mepians sing one longer and off-key note. Meanwhile, when mepians get paralooped or eaten, their scream is shriller than nightopians' as well as being  distinctly two-toned. Interestingly, two unused sounds exist in the game's data next to the other a-life sounds that also seem to have been intended for use by nightopians and mepians, respectively, with the first one (presumably for nightopians) having a softer quality and a slightly higher pitch.

Behavior Towards Other A-life

Nightopians have an innate fear of all nightmarens and mepians. Their mood can be negatively affected if the player touch dashes a nightmaren in their direction, while being positively affected if the player paraloops a nearby nightmaren or mepian. They will flee in the opposite direction of any nightmaren or mepian they encounter. Mepians are the opposite. They have no fear of each other or nightmarens. They are also unaffected by the player's actions toward nearby nightmarens and mepians. 

Nightopians and mepians have different mating behavior. Nightopians will only breed with another nightopian, and only if both have a full "desire to mate" value. If either partner is not ready, they will both ignore each other. Mepians treat normal mepians, but not badpians the same way, only breeding if both mepians are ready. 

Toward nightopians, badpians, and nightmarens, however, they don't check if the other partner is ready to mate and will pursue it regardless. Nightmarens and badpians are oblivious to the mepian's advances and when they collide, the mepian sometimes gets eaten before any egg can appear. 

On the other hand, nightopians actively avoid a mepian pursuing them. But if the nightopian doesn't get far away in time, the mepian can catch up and force it to breed by colliding with it. There's no reasonable explanation to why they were programmed to do this, aside from the developers wanting them to decrease the nightopian population and choosing a particularly sick way to go about it. More in the "Effect on Population" section.

Other Differences

The game treats mepians and nightopians differently. Paralooping a mepian grants the player 80 points to their score, while a nightopian grants 0. Paralooping three nightopians will cause the moods of all other nightopians to drop to 0 immediately. However, the player can paraloop any number of mepians without consequences for either mepians' or nightopians' mood. Also, paralooping 5 nightopians, but not mepians, will cause the "Please take care of Nightopian" hint to appear at the end of the stage.

There is a nightopian that appears over the Ideya Palace in mare 4 that grants bonus points for every star chip the player has collected until that point. Paralooping any nightopian will cause it to disappear, but paralooping a mepian will not.

Mepians have a shorter wait time before they are ready to breed again. For nightopians, it takes about 5 minutes, but for mepians the wait time is about 3 and 2/3s of a minute.

Badpians

Badpians are a type of mepian that is essentially the opposite of king pians, having only nightmaren parts. Like nightmarens, which they strongly resemble, they can eat any a-life they touch, including another badpian. Unlike nightmarens, they don't actively pursue a-life for eating, which possibly makes the badpian's case a bit sad. They just happen to kill anything they bump into. 

Effect on Population

Nightopians have a fairly low rate of reproduction. They have a base lifespan of 60 minutes, have to wait 5 minutes before they can reproduce, and each egg takes 20 minutes off their lifespan. This means a pair of nightopians can have a maximum of 3 offspring before they die. This is just enough to increase their population. Some nightopians may not even live to have 3 offspring, either because of being eaten by a nightmaren, paralooped by the player, or simply being located far from another nightopian. 

Mepians have a major advantage over nightopians in being able to have a longer lifespan. Any mepian that inherits a nightmaren torso part will have a lifespan of at least 100 minutes, while those with a Hollow or Snip torso will have 160 minutes. This means they can have as many as 7 children (it would be 8 if there was no wait time between eggs) before they die. Their shorter wait before reproducing also allows them to breed faster than nightopians, leading to greater population growth of mepians. 

Mepians' tendency to force mate with nightopians lowers the birth rate of nightopians. This is because the chances are high that their offspring will be a mepian rather than a nightopian, with the chance varying from 50-93.75% depending on how many nightmaren parts the mepian has . 

All of these things can contribute to mepians' population increasing over time while the nightopians' population decreases. Unlike mepians, which can always be created by the player throwing a nightmaren ball, nightopians will go extinct permanently once none of them remain in the population. This is because a pairing of two mepians can't have a nightopian offspring, if their offspring were to inherit all nightopian parts it would instead become a king pian. And since king pians don't reproduce, nightopians can't reappear unless the a-life is reset.