One of the minigames involves controlling a crocodile in a 2D platformer-style environment. The point of the game is to fall down the hole and land in the flan.
What you need to do for this trophy is take the high route to the end of the level. Jump on the platforms to get as high up as you can and run to the end. You'll reach a wall that will stop you from going any further. When you run into this wall, backtrack until you find the hole in the floor and jump through it. You'll get a bad score but the trophy will be yours.
Flan-tastic.