Number One is a Passive Collectible in The Binding of Isaac: Rebirth. It makes Isaac urinate instead of cry.
Isaac gets a 1.5 Tears up, a 15.78 Range down, and a 0.45 Tear Height up. His tears are now yellow and shoot from his lower region.
Number One is only found in the Item Room pool.
- Azazel: Azazel's range is reduced in exchange for reduced charge time.
- Brimstone: Isaac's laser takes much less time to charge while having no decrease in range.
- Marked: Isaac's tears are now orange.
- Mom's Knife: Isaac's range is reduced.
- Technology: Isaac's laser takes less time in between firing while having no decrease in range.
- Toothpicks: Isaac's tears are now orange.
- Incubus: Incubus' fires more quickly with no range down.
- To "go number one" is to urinate.