Bullyball

Overview
BullyBall is a multiball orb that was introduced in the Demo Release. Its name is a portmanteau of “Bully” and “Ball.” Like other multiballs, it can interact with several board effects and has a few quirks tied to how it leaves the pegboard and how it receives damage.
BullyBall is built around self-damage: taking damage to yourself increases its strength, making it one of the more volatile orb types to scale over a run. Damage from Rigged Bombs counts as self-damage, and damage from relics such as Wand of Skulltimate Power also counts. A healing source is highly recommended if you want to grow a strong BullyBall, since it can quickly eat away at your health while you are building its damage. Popping Corn, Infernal Ingot, and Nosforbatu are all useful for offsetting the cost, with Nosforbatu also boosting BullyBall's damage directly. Gardener's Gloves can help reduce the HP loss needed to power it up.
BullyBall also has notable synergy with Infernorb, Orblation, Nosforbatu, and Wand of Skulltimate Power. It appears among the source list for several orb-producing or duplicating effects, including Matryorbshka, Matryoshka Shell, Double Trouball, Duplication Station, Circcae, Potion Ballt, Duplicatorb, and Gopher Gold.
- If self-damage is negated, the damage may not contribute to BullyBall's strength in some versions.
- Rigged Bombs and relic-based damage count as self-damage.
- Its multiball behavior had several bugfixes: issues with getting stuck in the easy shield encounter, not lighting up correctly with Allorbnothing, and escaping the board with Gift That Keeps Giving were all addressed.
- Later changes also prevented multiballs from continuing to trigger morbid effects on moving pegs after leaving the pegboard.