Gives Isaac a flat +0.75 fire rate even past the normal cap, -0.03 speed and distorts the screen and background music. The effects can be stacked in the same room, and the distortion becomes more pronounced with repeated use.
Each use increases the recharge time, with the 9th use having a recharge time of 15 seconds. After the 10th use, it no longer recharges automatically though it can be recharged and used even more through batteries.
Leaving the room doubles the speed penalty and multiplies the fire rate bonus by x0.4, for the uses in that room.
Clearing removes one use's worth of penalties and bonuses, giving +0.06 speed and -0.3 fire rate.
Isaac's costume will change the stronger the Item's effects get.