Aqua Pirate

The Aqua Pirate is a Space Pirate underwater trooper found in Metroid Prime.

It is in many ways exactly like the Flying Pirate, except for the fact that it only travels underwater. It has an aqua jet pack, and has the same attack patterns as the flying pirates do, complete with the kamikaze attack it makes once critically injured. The only difference besides being underwater is that it is slightly slower. Aqua pirates only appear in Metroid Prime. This suggests the Space Pirates either saw no use for them, or found them inadequate weapons and ceased pursuing the idea.