Leon S. Kennedy encountered the U-3 (or "It" as Lord Saddler called it) on Saddler's island base and fought against it inside a suspended set of crate rigs. He was able to avoid its attacks and escape the rigs before they all dropped into the chasm below, but the U-3 also escaped and attacked again on the cliff at the other side of the chasm. The monster mutated as it attacked, its back tearing open as its spine erupted from it, sporting a large pair of sharp pincers capable of snapping a man in half. It was also capable of burrowing beneath the ground so that it could take Leon with a surprise attack. After a frantic battle, Leon managed to kill the U-3 by destroying the parasite in its body.