when thrown and collides with entity, ender pearls act like snowballs and causes a damage flash and aggro from entities. notably villagers are caused to create negative gossip, (villager spawned) Iron Golems get aggro and zombie pigmen get aggro.
MC-158045
Ender pearls damage entities
Resolved
Invalid
0
As far as I'm aware, this has always been the behaviour of ender pearls, and is most likely intended.