Skull

Verified against the spelunky.ai port v0.1.10 on 27 October 2026.

It's thrown like a Rock, but breaks like a Jar, into one or two bones, with nothing inside. It's left wherever bones are: beside the piles level generation scatters, and where a Skeleton, a Zombie or a Vampire falls apart.

A Skull is picked up and thrown as any item is: crouching over it with empty hands, the attack key lifts it, and the attack key throws it ^{[3] [4]}. Its movement code is the Jar's: it falls 0.6 pixels a step faster each step until it's falling at 6 or more, and bounces off walls and floors ^[5]. It breaks more easily than a Jar, when it:

• hits a ceiling going up, at any speed: its test is for a speed below 2 pixels a step downward, which always holds for a Skull going up ^[6];
• hits a wall faster than 2 pixels a step across, or lands faster than 3 ^[7];
• touches a monster or a Damsel while moving faster than 2 pixels a step ^[8];
• is hit by a bullet or an explosion, or sinks into lava ^{[9] [10] [11]}.

Breaking, it leaves one bone, and a second with a 1 in 2 chance ^[12].

A Skull does to a monster what a Jar does, by a copy of its code: it picks the monster nearest it, stuns a Caveman, a Hawkman, a Mantrap, a Yeti or a Shopkeeper without hurting it, takes 1 hit point from any other that isn't invincible, and breaks ^{[1] [13]}. In the clip, the player drops off a ledge with a Skull and throws it at a Snake on the ledge beside him: it breaks on the Snake and kills it ^[14].

• Piles of bones. Level generation puts piles of bones on blocks with open space above them in the Mines, the Jungle, the Ice Caves and the Temple; 7 in 8 of them are plain bones with a Skull beside them, the rest rise as a Skeleton ^{[15] [16] [17]}. The Skeleton's page has the odds.
• Dead monsters. A Skeleton, a Zombie or a Vampire that dies falls apart into three bones and a Skull, thrown upward ^{[18] [19] [20]}.
• The player. A Ghost's touch kills him outright, and his body falls apart the same way ^[21].
• The level editor's k tile, a pile of bones with a Skull beside it ^[22].

• Whip. The Skull has no code for it, so the Whip doesn't break it, unlike a Jar.
• Pitcher's Mitt. Like a Jar, a Skull thrown with it keeps the Mitt's lighter gravity for good ^[13].
• The screen. Most items stop once they're 16 pixels off the screen; a Skull's code has no such test, so it keeps moving until the level puts everything far off the screen to sleep ^{[23] [24]}.
• Exits. Carried through a level's exit, it's in the player's hands on the next level, whole ^[25].

• A Skull thrown upward under a low ceiling breaks on it, whatever its speed.
• A Skull only stuns a Caveman, a Hawkman, a Mantrap or a Yeti, where a Rock also takes a hit point.

• The Skull's step is the Jar's with the Jar's name changed, but its thresholds for breaking are lower, and its test for the ceiling, yVel < 2 inside a test for yVel < 0, can't fail, where the Jar's is yVel < -3 ^{[6] [26]}.
• The number of bones is rolled anew on each pass of the loop that makes them, i < rand(1,2): a first bone always, then a second on a 2 ^[27].