Space Sharks

Space Sharks are giant mechanical sharks that surround Ice Planet.

Role in Astro-Knights Island
The 3 space sharks guard Ice Planet, not letting you near it. Even if you get past them, it won't be safe enough to land on the planet. However, Sir Gawain somehow managed to land on Ice Planet without defeating them. According to the spaceship databank, the sharks are practically indestructable.

Role In Poptropica Adventures Nintendo DS
Space sharks make an appearance in a minigame in the Poptropica Adventures Nintendo DS game. They chase you through space on Astro-Knights Island.

Weaknesses
It appears that the space sharks have very few weaknesses, one of which is a Black Hole. Aside from that, the space sharks are also rather slow and will give up chasing you if you fly too far ahead.

Trivia

 * They are similar to Mutant Glump Sharks from Moshi Monsters Season 2 Mission 9: Missing On A Star.