Sprunki is a horror Incredibox mod that originated from the Scratch website made by NyankoBfLol, later officially ported to Incredimake before it got taken down.
The gameplay is the same as Incredibox as it is a mod. You drag one of the 20 character icons on the bottom of the screen onto one of the 7 empty polos. However, once you drag the Black top-hat icon, the game will go into horror mode after a temporary black screen, with all the characters being either injured, insane, or traumatized.
There is also a reset button on the top right corner of the screen that resets the characters.