Tinies Are Delicate

By default, tinies will receive more damage the smaller their scale, this can be disabled in the Server Config:

actuallysize-server.toml 

# This enables this feature in which tinies receive increased damage

tiniesAreDelicate = true

# This disables this feature in which tinies receive increased damage

tiniesAreDelicate = false

This deals with environmental sources of damage, where another entity is not attacking you — essentially lava, fire, lightning, anvils, etc. The list is pretty large when you actualy get into it. A special case is fall damage, since ASI does not affect it, but Pehkui does, so yes tinies do receive increased fall damage, but it is not ASI doing it.

There are some exceptions, the following sources of damage are not increased:

• Starving in hunger

• Drowning in water

• Damage from falling into the void or world border

• Damage from wither effect

• Damage from /kill

• Entity cramming 

• Being stuck in a wall

• Dragon breath

• Damage from touching cacti¹

• Damage from standing on magma blocks²

• Damage from flying into walls very fast with elytra

• Damage from sweet berry bushes¹

1: These kinds of prickly damage sources maybe should do more damage to tinies, because well, thorns would be like swords to them. However, I also feel that tinies would not have much problem not being impaled by these things, in the same way bugs can climb cacti just fine. Then, tinies below 0.25x scale straight up don't take this damage anymore.

2: Magma blocks SHOULD deal increased damage to tinies, and crouching should not help you, but this would be unecessarily annoying really so let's just leave it at normal damage. Maybe in a future update magma blocks will be adjusted, because I like the idea that tinies really need normal players to be carried over magma blocks that are otherwise impassable xP