A cannon pointing downwards
Cannons are grey, with black borders. One end is flat, indicating where the cannonballs shoot out from while the other end is round, which is attached to the ground or ceiling. The cannonballs shot out are round black pixels.
At a relatively fast pace, cannons shoot out black cannonballs. The cannonballs will keep travelling in the same direction they initially were shot out from until they hit a wall, ground or ceiling.
They will then splat and cover the area with black. The cannons themselves will not hurt the teeny hero on contact, however, the cannonballs will kill him and force him back to the last checkpoint touched. Cannons also appear on the last two levels of the game.