Instant Health

Instant Health is a instant status effect which increases health for living mobs and damages the undead.

Effect
Instantly heals × 2level. Undead mobs (including the wither) are damaged as if with Instant Damage, instead. If the effect is forced to last longer than one tick, it will heal entities every tick. Levels 30–32 provide no healing. Amplifiers outside the range 0–31 (corresponding to levels 1–32) are used modulo 32.

Immune mobs
Effects vary on undeadness, but no mobs are immune.