The host of BFB. An algebraic alien in the shape of the number 4. Non-binary, but with a strong masculine personality. Possesses various superpowers. Notable abilities include Zappies (laser beams), Screechy (a chalkboard-scratching scream that stuns others), Mutilation (transcendental reality warping that twists contestants into grotesque shapes to kill them while harp music plays), and recovery/revival. Telekinesis and flight are standard for him.

The co-host of BFB. An algebraic alien in the shape of the variable X. Non-binary, but with a strong feminine personality. Four's best friend. Can use superpowers like Four. Mainly uses telekinesis, levitation, regeneration, and can walk through lava unharmed.

A green latex balloon. Male. The first one to be infected by the glitch.

Bubble: A soap bubble, female. Pops easily but can be recovered. Friends with Ruby. Ruby: A brilliant-cut ruby, female. Very sharp and cheerful. Friends with Bubble. Leafy: A lemon leaf, female. Light enough to be blown by the wind and very agile. Can teleport using a map. Friends with Firey. Lollipop: A grape-flavored lollipop, female. Friends with Gelatin. Has a very unnatural laugh. Developed "Fork Repellent" which can block not just forks but the flow of liquids like lava. Teardrop: A teardrop, female. Silent. Can fire a laser from her fingertip. Blocky: A wooden building block, male. Loves pulling pranks. Friends with Woody. Woody: A balsa wood plank, male. Very cowardly. Friends with Blocky. Firey: A flame, male. Dies if he touches water and is afraid of heights. Friends with Gelatin and Leafy. Loser: A cube, male. The most popular and famous among the objects. Spongy: A kitchen sponge, male. Smells a bit and is slow due to his size. Can absorb water.