Number One

Number One is a passive item.

Effects

 * +1.5 tears.
 * -17.62 range.
 * +0.45 tear height.
 * Tears turn yellow and are fired from Isaac's lower body rather than his head.

Interactions

 * Azazel: Lowers range, reduces charge time.
 * / : Tears often disappear before being able to split. Split tears also only travel a very short distance.
 * : Tears disappear very quickly after being fired and split tears barely travel at all.
 * : Not recommended. Bombs do not travel far, making self damage very likely.
 * : Does not affect main tear; however, burst tears travel significantly less far.
 * : Tear barrage fires a very short distance before disappearing. Does not affect the stone.
 * : Tears still increase in size and damage as they travel; however, the short range limits tear size and damage.
 * : Tears become orange. Firing rate is increased, Marked's effect is unaffected but range is reduced.
 * : The knife turns yellow and the maximum range is significantly reduced.
 * /: Not recommended. Tear barrage disappears very close to Isaac.
 * : Not recommended. Tears disappear after traveling a very short distance.
 * : Tears often disappear before being able to bounce off walls.
 * : Tears become orange.

Synergies

 * : The laser turns yellow and charges at a much faster rate with no decrease to range.
 * : Increases firerate with no decrease in range. Explosive clouds are now yellow.
 * : The Incubus fires at a much faster rate with no decrease to range.
 * : Increase fire rate moderately and decreases range only slightly.
 * : Turns tear yellow and allows it to be moved much faster.
 * : Eyeball tears are yellow, can be fired much quicker, and does not affect their airtime.
 * : The laser turns yellow and Technology's firing rate is greatly increased with no decrease to range.
 * : Laser turns yellow, charge time is greatly decreased, and no decrease to range.
 * : Tears travel roughly the same distance but can be fired much quicker.

Trivia

 * "Number One" is a euphemism for urination.
 * In the original Binding of Isaac, Number One had the effect of turning all future Range Down pills into Range Up pills. This was presumably designed to reduce the risk of players being stuck in situations where their range would become too low to clear certain rooms. However, in Rebirth, Number One no longer has this effect, and will not turn Range Down pills into Range Up pills.
 * This item is used in Challenge #2 (High Brow).
 * The firing animation of Number One is a little different from what it looks like in the original Binding of Isaac.

Seeds
J172 PRAK (Treasure room adjacent to spawn) VMA3 SMZA (Treasure room adjacent to spawn) SRX8 FXHM (Treasure room adjacent to spawn) (XL floor) (Hard mode only) 0RJ7 VQYY (First floor treasure room) WYH4 A4DX (First floor treasure room)