Do you remember in world 2, 5, and 6 where the Perry Block tells you about a star-shaped enemy? For those who want to see him, go to the following areas:

Hoo's Wood (Level Five): In the second room, if you see a Starfish doing the backstroke, wait until he jumps out of the water. Then nail him as many times as possible.

Wavy Beach (Level 5): In the last room, walk as slow as molasses by holding L or R. When you see a Starfish sleeping on a towel, walk (still holding L or R) over to it and give it a rude awakening.

Gleam Glacier (Level 4): In the last room, you will see a Starfish on the platform above you. Run until you reach the hill, then use the Gloom vibe and DASH like heck. If you are ahead, stop bawling and teach him karate with an umbrella.

Starfish will only appear in these rooms 30% of the time, so if he's not there or he escapes, exit the room (but not the level) and reenter the room.