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These bombs have the same appearance as Sticky Bombs, but do not spawn spiders.
Explosivo: Bombs have a chance of sticking to an enemy. Cricket's Body: Bombs split outwards into 4 tiny bombs, which detonate almost immediately. Both the explosion and the cloud effect deal full damage. Unlike normal Butt Bombs, this synergy cannot heal Brownie, Clog, Colostomia, Dangle, or Dingle. This maximizes at 100% at 26.67 luck and minimizes at 0% at -6.67 luck. The chance is 20% at 0 Luck, increasing by 3% per luck. The activation rate is now random and dependent on luck. Butt Bombs: All bombs inherit the Butt Bomb effects. This maximizes at 100% at 29.67 luck and minimizes at 0% at -3.67 luck. The chance is 11% at 0 Luck, increasing by 3% per luck. Brimstone Bombs: The activation rate of the Brimstone lasers is dependent on luck. Blood Bombs: Bombs leave behind a pool of red creep. Bomber Boy: Bombs explode in a large cross-shaped pattern. Homing Tears: Bombs home in on enemies. Euthanasia bombs do not retain the instant kill ability. Apple! / Euthanasia: Damage multiplier may be applied to the non-flat damage without a visual difference. This includes effects from bomb modifiers, not just raw base damage. Self-damage is increased to a full heart if the bomb would deal 85 damage or more.
Fetus bombs deal half a heart of damage to Isaac.
Many more synergies have been added, and all passive bomb modifiers affect Dr. Fetus overrides multiple tear effect items, but benefit from some (but not all) bomb-enhancing effects like Mr. Angelic Prism Split bombs still deal knockback to eachother.
Bombs grow larger or smaller with tear size modifiers and deal no knockback to each other. Delay before the explosion is not affected by either. The range and shot speed stats both affect the velocity at which the bombs are fired out. The flat 30 is not affected by damage multipliers. If the previous formula would lead to the bombs doing more than 60 damage, the bombs instead deal 5 times the character's normal tear damage plus a 30 flat damage. At first, each bomb deals 10 times the character's normal tear damage. Fetus has two formulas for calculating the damage it does. Each bomb deals 5 times the character's normal tear damage plus a flat 30 damage. Each bomb deals 3 times the character's normal tear damage. Tears are replaced with bombs that explode approximately one second after being fired.