Explodemon

When exploding near an enemy by using the button, you have a chance of performing a counter. A red button flashing to be pushed will appear above you; all you have to do is push the button to explode again and you will get it. I found that the spawn machines are a guarantee to give you the chance to counter. Jump up next to one and keep pushing the button to explode and the trophy will pop. Should be one of the first trophies you get in the game.