So we came up with our idea at 2AM and decided on doing a platformer game in which the player would be on a sinking floating island where a indefinetly growing creature under the island would fill all the underground tunnels and pull the island down. The player would win by completely destroying the creature and would lose if the island sinks or if the creature crushes them.

We've drawn some graphics and managed to set up a platformer engine but we're stuck on handling the creature's growth by spawning blobs.