Limb gumballs are items that remove limbs when eating and give them to their owner. They are owned by Yellow Face.
It first appeared in "The Seven Wonders of Goiky". Ice Cube asked Yellow Face what it was, and Yellow Face said it was a gumball. Ice Cube ate the gumball, and her legs came off. Ice Cube said why Yellow Face didn't say it removes legs, but Yellow Face. The stinger shows the legs went on himself.
In "Balancing P.A.C.T.", Donut ate it, and his arms came off. Yellow Face wished he had Winner's hand, so he asked them, "a gumball?"
The gumballs may be based on those found in "Barriers and Pitfalls", since they are both gumballs with solid black outlines associated with Yellow Face.