Java Edition:Phantom with Poison or Regeneration
Phantoms with Poison or Regeneration were obtainable before they were considered undead mobs. The Poison or Regeneration effects will eventually run out, making this a temporary discontinued feature.
Obtaining
From 18w07a to 18w10b (1.13 snapshots), phantoms were not undead mobs and could get poison and regeneration like any other mob. However, in 18w10c phantoms were changed to undead mobs, so poison and regeneration could no longer be applied to them.
Variants
Poison 1 can have a duration of up to 1:30 and poison 2 can have a duration of up to 0:21.6 using splash potions.
Regeneration 1 can have a duration of up to 1:30 and regeneration 2 can have a duration of up to 0:22.5 using splash potions.
In later versions, the duration of the potion effects can be decreased by loading the phantom but the duration cannot be increased.