Catch of the day Trophy in Radio Squid

This will be the last trophy you earn before the Platinum. Like the previous two, there are multiple bosses available on the third floor. Find and kill any to get this trophy (see Got a Bite). The one I did, which was on the upper-left path, was not only the easiest boss I've faced but probably much easier than many of the normal rooms with normal enemies. It was what looks relatively like the Muk Pokemon; it looks like a slug. It shoots fireballs but only in one direction i.e. either horizontally or vertically, not both. Over all, it's a very easy fight.

Here is a video showing the path to the boss, starting from the beginning of stage 3–4, and the fight: