Blooper

Bloopers are squid enemies that follow Mario around. They also work on non-underwater levels - they will fly around as if in water. If they are not underwater, they can be stomped.

If you shake one, it turns into a Blooper Nanny, a blooper that is followed by four Baby Bloopers. If you knock out the nanny, all the babies will also be knocked out, but you can also knock out the babies individially.