Sea Attacker

Sea Attacker (シーアタッカー) are seahorse robots that are in Launch Octopus's stage. They shoot up from below (bubbles indicate that they'll appear) and after being stationary for a moment, they roll up and speed toward X. From Mega Man Maverick Hunter X they also appear in the first Sigma level right before X faces Launch Octopus.

Sea Attacker ST
Sea Attacker ST is a modified Sea Attacker from Mega Man X6 that appears in Rainy Turtloid's stage.