Spider

Verified against the spelunky.ai port v0.1.8 on 27 October 2026.

Level generation hangs Spiders under blocks in the Mines, where each waits for the player to walk beneath it; elsewhere, Spiders come out of Jars. Once it has dropped, a Spider hops after the player in short, high jumps and bites him on contact. With 1 hit point, it dies to any damage, whether from the Whip, a stomp or a thrown Rock.

A Spider starts out hanging under a block, still. It drops when the player is below it, within 8 pixels of its middle across and within 90 pixels of it, or when the block it hangs from is gone ^[4]. The clip shows one dropping as the player walks beneath it and leaping onto him.

Once down, it falls under gravity and moves only by hopping. It waits 5–20 steps (0.17–0.67 seconds), then jumps up at 2–5 pixels per step and across at 2.5 pixels per step, toward the player ^{[5] [6]}. While the player is within 90 pixels, it jumps at him again each time it lands, with a 1 in 4 chance each time of stopping to wait again instead ^[7]. Farther away, it makes a single hop toward him after each wait ^[8], so it closes in from any distance, only more slowly.

A Spider that falls into water drowns: it stops, sinks, and is removed 30 steps (1 second) later ^{[9] [10]}. It only acts while it's on screen or just off it ^{[11] [12]}.

When the player touches a Spider without stomping it, he loses 1 heart, is knocked away from it, and blinks, invincible, for 30 steps (1 second) ^[13]. This is the touch code most monsters share; the Spider has no attack of its own, and the clip above shows a leap that lands on the player taking him from four hearts to three.

A Spider has 1 hit point, hanging or after it drops, so any damage kills it ^{[14] [15]}:

A hanging Spider runs its own step event in place of the one most monsters share, so the hazards in that event (Spear Traps, Spikes, Lava) only reach a Spider once it has dropped, when its step event runs the shared one first ^[25].

Spiders killed count toward the player's kills, and the screen between levels draws a Spider icon for each ^{[26] [27]}. One that Spikes, Lava or a Spear Trap killed doesn't count ^{[28] [29] [30]}, nor does one that drowns, which is removed without dying.

Level generation makes Spiders only in the Mines, hanging under blocks that have two blocks of open space below them (with no water there and no monster right under them), outside the starting room and shops and above the level's bottom 64 pixels. For each such block there's a 1 in 80 chance of a Spider once the rolls before it have failed: a Giant Spider, on a dark level a lamp or a Scarab, and a 1 in 60 chance of a Bat ^[31].

Spiders also appear wherever these are:

• Jars. A broken Jar makes a Spider with a 1 in 6 chance once its rolls for gold and gems have all failed ^{[32] [33]}.
• Olmec's yellow balls, which turn into a Bat, Spider, Snake, Frog or Fire Frog when they hit the ground ^[34].
• Kali's altar. The first time the player destroys one, Kali's head above it releases six Spiders, and it does again on a later one if the level is dark and the Ghost is already out ^{[35] [36] [37]}.
• The Stars room, a bonus room off the high-score room, where a Spider may drop in from the top every 20 steps, more likely the more Shopkeepers the player has killed there ^{[38] [39]}.
• Custom levels, as the level editor's tile s, a hanging Spider ^[40].

• A hanging Spider only drops for a player below it and within 8 pixels of its middle across, so one can be passed on the ledge above it, or beside it, without it dropping.
• Out of range, a Spider still hops toward the player after every wait of 5–20 steps, so it keeps coming.
• Water kills a Spider that falls in, but the kill isn't counted.

• The Spider's code names a walking state, but nothing ever puts it in it: a Spider only ever waits, hops or drowns ^[41].
• A commented-out block in its step event would have reversed it at walls ^[42], and the Jungle's generation has a commented-out line that would have hung Spiders there too ^[43].