Cool your head.
Just run into the water and wait. The treasure chest will appear near the water.
*King Caterpillar x3, Skeleton, Yellow Ahriman, Caterpillar, Red Caterpillar
The main part of this stage is defeating the 3 king caterpillars. Doing so will take a long time as they have a high amount of HP. Their actions are similar to both their lesser versions: rolling and letting off a shield of red puffs of smoke. Using combination magic will greatly help here. Stay away from the walls to avoid getting trapped by the king caterpillars. If you get trapped, you're as good as dead as the king caterpillars will keep rolling and moving towards you, and since the other two are there, they can't move any further while you're taking the damage.
Once you get rid of them, you can take care of the rest of the enemies still around. Note that the skeletons in this stage do not require elemental damage to get rid of. Prior to defeating the 3 king caterpillars, the lesser enemies will respawn randomly if you keep defeating them.
