Magmaw

Magmaws are a species of Blarggs in Super Mario Galaxy 2 found exclusively in the Melty Monster Galaxy. Magmaws live in lava and attack by opening their mouths and passing through asteroids the player may be on. They seem to be mostly liquid because small objects such as meteors can pass through their body. Much like their larger counterparts, they are unbeatable and cannot be harmed.

Trivia

 * Magmaws bare a slight resemblance to Bogmire from Luigi's Mansion, both in appearance and the sounds they make.