Plays an animation on the entity. This may not always work on engine entities.
Will not work on players due to the animations being reset every frame by the base gamemode animation system. See GM:CalcMainActivity.
For custom scripted entities you will want to apply example from ENTITY:Think to make animations work.
Minimal code needed to make sequences work as expected on custom "anim" type entities.
In this example, when the player uses the crate, it will open, and when they use it again, it will close.