Speed

Speed is a status effect which increases a player's (or mob's) walking speed by 20% multiplied by the effect level. It expands a player's field of view (FOV) accordingly. Negative levels will decrease speed.

Immune mobs
No mobs are immune to Speed.

Trivia

 * Speed allows slimes to jump farther. High levels of speed can make slimes bounce out of view with just one jump.