He tries to eat Wart and Merlin in their fish forms. Although not exactly evil, he is treated like a villain, but just wants to eat, and chases the two, with Merlin locked inside a knight's helmet where he'll be safe. Meanwhile, Wart outsmarts the pike by ramming into the chains, allowing him to hide behind a wall. But the pike frees himself and corners Wart behind, but Wart tries to defend himself with an arrow, and the pike pursues Wart and is rescued by Archimedes as the pike slams into a rock before his prey escaped.
Of course, afterwards, Merlin changed himself back into his human form before pulling off the knight's helmet and then tossing it aside before remarking that he would turn the pike into a minnow.