Specter

Specters are a possible Evolution of Infected Wandering Traders that can only occur when Linked, belonging in the Combat Abnormal tier. They are highly proficient, stealth-focused melee combatants.

Spawning

Evolved from a Linked Infected Wandering Trader when it obtains at least 1 Evolution Point and its 5 minute Evolution timer expires. Once it does, it will Evolve into a Specter.
Can be spawned by Challenge Watchers as a special mob during a Challenge Raid.

Unique Behavior

When a Specter's current target is farther than ~7 blocks away, the Specter will 'cloak' itself, becoming invisible, and slowly walk towards its target. While cloaked, Specters don't emit idle noises and can't be detected by Sculk Sensors. Once the Specter gets within ~7 blocks of its target, it'll uncloak, becoming visible and regaining its faster speed. Cloaking and uncloaking are accompanied by SFX designed to spook nearby players.
If a Specter detects a container holding food within a 32x4x32 block area of itself, it'll pathfind towards the container and open it, consuming a large potion of the food inside. If, during an instance of eating food, if the container runs out, the Specter will destroy it. For each item a Specter eats, the hunger and saturation values of each food item are added together; that number is then added to the Specter's 'stomach' value. Every 10 seconds, a Specter checks its internal stomach value; if the value is above 10, then 10 is removed and the Specter receives 1 Kill Point.
Whenever a Specter is damaged by a living entity, there's a 10% chance the Specter will spawn a Scent directly below it.
Specters, while idle, if detecting any nearby light sources, CDUs, or TNT, will pathfind towards them and destroy them.
Specters inflict Blindness I for 5 seconds when dealing melee damage.
Cannot ride Boats.
Specters are able to climb blocks, similarly to Spiders.
Specters are aquatic; they can breathe underwater and swim fast in liquids.
Specters granting themselves Regeneration with Kill Points will receive it for 20 seconds. If below 50% health, it'll be Regeneration II as well.
Specters take 50% less damage from fire damage.
Can fall from up to 19 blocks before taking fall damage.
The melee attack of Specters deals 3 knockback.
Specters have a step up height of 1, meaning they don't have to jump to go up blocks that are 1 block tall.
Specters are completely ignored by the Despawning System.
Will despawn during Proto World Modifier if they are at least 256 blocks away from a player.

Behavior

Specters are hostile to most non-Spore mobs, with the exceptions being Animals and Fish (unless Should attack Animals is enabled via the Config) and mobs included in the Mobs Not Targeted blacklist within the Config.
Specters inflict Mycelium Infection II for 10 seconds when dealing melee damage.
Capable of breaking blocks with a hardness of 3 or lower.
Can perform short dashes in liquids to pursue a target. However, since they can swim properly, this mechanic is never utilized by them.
Able to utilize Kill Points to grant themselves buffs.
Present a weakness to the cold.
Will despawn during Proto World Modifier if they are at least 256 blocks away from a player.
Are not affected by Vanilla Despawning.
In regards to Frostbite, have a Body Heat of 4 and Enum Percentage of 5%.

Related Advancements

Drops

Armor Fragment (80% chance for 2 - 9)
Claw Fragment (80% chance for 6 - 9)
Fang (50% chance for 1 - 2)
Innards (50% chance for 1 - 2)
Mutated Fibre (80% chance for 5 - 17)
Mutated Heart (10% chance for 1 - 3)
Tendons (60% chance for 3 - 7)
Tumor (100% chance for 4 - 8)

Lore

Due to the Infected Wandering Traders that Specters evolve from drinking many Potions of Invisibility, they become able to turn invisible on demand.
Specters, unlike most other Spore Mobs, are capable of their own thought and acting on their own accord. This is due to them being one of the most intelligent Mobs in the mod, excluding Proto Hiveminds and similar mobs.