Isaac's Fork is NOT a valid synergy since it doesn't drop a red heart but instead just heals your character after clearing the room. This has to be edited.
another seed, item room south of starting room Z76F WP12
how over powered this thing is: platinumgod.co.uk/dark-bum
Dark bum is a great synergy with Azaezel, if you manage to get one heart.
Dark Bum is good with the Jar, as it allows you to store extra health in the jar, and if you manage to get the jar and Humbling Bundle you can get infinite red hearts which turn into infinite soul hearts
Possible Bug
If you use the credit card in a shop that has a red heart as an item for purchase it will become a free pickup. The dark bum will repeatedly attempt to pick up the free red heart but be unable to consume it.
Dark Bum dropping bombs
I have noticed in a recent playthrough that Dark Bum sometimes drops normal bomb pickups. I also had Fanny Pack, but I don't think I was hit when this happened. Can anyone confirm this?