Acuba

Acuba (突撃水兵 アクバ一 Totsugeki Suihei Akuba Ichi?, lit. "Assault Frogman Acuba") is an enemy in the Contra series.

Gameplay Description
He is a scuba sharpshooter soldier who has been brainwashed by the Red Falcon's forces. He is found in the waterfall stage in the game. He is first encountered hiding in a cascade's streams and he cannot be killed in this state. However as the player scrolls up, he will begin attacking by quickly emerging from the stream to fire a projectile that will explode and divide into three shrapnels which will then rain down, effectively covering a considerable area.