A six-legged spider with small, red eyes.


Makes a large bite mark come out of Isaac's head.

Gives Isaac's shots a 25% chance of slowing enemies for 2.5 seconds. The projectiles from a slowed enemy are also slowed but retain their air time, effectively reducing their range. Turns tears white.

This will typically work against invulnerable creature or creature parts, such as Stone Grimaces in The Depths, Mask + Hearts, and against Knights from the front.




  • In the Spiderboy Challenge, you start with this item and the Mutant Spider.
  • This item is probably a reference to The Amazing Spider-Man, where a spider bite from a radioactive spider gave Spider-Man his super powers.

Related Achievements

"The Radioactive Spider" - Complete The Basement once.
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