Not to be confused with Dagon, the character from Gargoyle's Quest II which has the same name but isn't related.
Dagon is the boss of Stage 3 of Makaimura for Wonderswan, a fish-like creature.
The Dagon mostly attacks with bubbles. One attack has the bubble floating in air through the ground towards at you. Dodge it jumping over it when it nears you. In another attack, it spits bubbles which float up in the air. Try to take those out if you can, because after these bubbles burst if left unatttended, three fish monsters will come out and chase after you. In another attack, it will spit goo at you, so you must avoid the attack. Like most bosses in Makaimura for WonderSwan, its weak point is its head, so you should aim your attacks at it.