A Cave Story crossover.

The Doctor is a madman. A ruthless, cunning madman. He has plans to wage war with the world and become the new leader. He has successfully obtained the Demon Crown -- an item granting the wielder powerful, evil magic -- amassed an army, and even developed a way to enhance his power further.

Quote and Curly Brace have followed this monster to the ends of the island to stop him and his nefarious plans. But it seems that the Doctor has a few more tricks up his lab coat. His plan is far greater than anyone imagined.

Now separated in a strange new land, the two must find a way to befriend the ponies of this world and protect them from the Doctor's arrival.

Because he's come declaring war. And with the power of a god, no one will be able to stop him.