Dark Bum

Dark Bum is a passive item.

Effects

 * Spawns a familiar that follows Isaac around and collects red hearts. For every one-and-a-half red hearts collected, Dark Bum will generate one of the following:
 * A single soul heart. This is the most common effect.
 * A hostile Spider.
 * A friendly Blue Spider.
 * A single black heart. This is the least common effect.

Synergies

 * Little C.H.A.D. - Convert hearts dropped by Little C.H.A.D. into Soul Hearts.
 * Gimpy - When enemies die and drop red hearts, they get converted into Soul Hearts.
 * Humbling Bundle - All red hearts dropped are double hearts, so the conversion ratio is greatly improved.
 * ??? - Greatly improves chances of survival, due to Dark Bum converting useless Red Hearts into useful Soul Hearts.

Patch Notes

 * Prior to Version 1.02 Dark Bum's red to soul heart conversion rate was 1:1, but it was set to 1.5:1 with Version 1.02.
 * Prior to Version 1.031, Dark Bum did not have a chance to spawn spiders of either kind. This was likely done to nerf its use with characters that start with no or few heart containers.

Seeds
WBEG Q22R (treasure room adjacent to spawn) CS9M XL2P (treasure room adjacent to spawn) AL07 13JY (treasure room adjacent to spawn) 7276 4P61 (treasure room adjacent to spawn) EVQ8 P80Q (treasure room adjacent to spawn)