Robot Piranha

The Robot Piranha is a robotic, fish-like creature that appears on Astro-Knights Island, on the Ice Planet. The fish are minor antagonists, due to the fact that they try to prevent you from reaching Slippy Mountain.

Role on Astro-Knights Island
When you first enter you need to jump from iceberg to iceberg over freezing cold water. Metal Piranhas will pop up out of the water and will occasinally hit the player. Most of the time, when a player gets hit, s/he will fall into the lake and will freeze, causing him/her to respawn at his/her rocket ship.

To get past them, don't try to jump over it, and keep your balance on the iceberg. The Metal Piranhas will eventually leap over you. Then jump to the next iceberg.

Trivia

 * The Piranha will sometimes actually help the player. If the player is above the water and between two icebergs, the piranha will sometimes knock the player back onto the iceberg.
 * The Piranha resembles a knight's helmet with a tail and a fin on top.
 * It is possible that the Metal Piranha is made of stainless steel as it never rusts, even though it lives in the water.