Splounders are enemies that first appeared in Super Mario 3D World.
Splounders are fish-like enemies that appear in Plessie stages. They either remain stationary or move from side to side. If bounced on, Splounders will allow Plessie to jump higher and sometimes get on top of areas or grab items that would otherwise be inaccessible. If Plessie bumps into a Splounder, it will become stunned and bounce Plessie to the side