I'm stuck on the second dungeon. The one where you are at the beach and you jump into a whirlpool and enter this foresty area. In the middle there are several entrances and each one looks like a monster's mouth. The middle one I got two keys and found a large tail and wacked it and the entrance to the left of the middle one opened. I exited the middle entrance and entered the left one. I got the two keys here as well and wacked the tail. After disappearing however, it did not show an animation with the monster's bead erupting from the ground like the first time around. I went back outside and there are no new entrances. Is this a bug or am I missing something?