It is a Strabby (named Sprout by Gramble) in a plastic ball, reminiscent of a hamster ball. Sprout is trained to follow wherever they are led by the laser pointer. This can be used to lure other Bugsnax to specific places.
As a tool
The Buggy Ball has a variety of uses. It can be led into small, inaccessible tunnels, chasing out a Peelbug that may be hiding inside. The ball can be covered in any sauce, which can be used to lure Bugsnax over great distances at a low sauce cost. The Trip Shot can even be attached to the ball, allowing the tripwire to be actively moved around.
Something to keep in mind while using the Buggy Ball is that curious crab-like Bugsnax can pick it up and carry it away. While not difficult to retrieve, a Crapple may cause it to land in the water, washing off any sauce. A Noodler or Stewdler will set the ball on fire, though having a controllable fire source can be used to the player's advantage.
Sprout is the Strabby within the Buggy Ball. It seems to be a "baby" Strabby, since it is smaller than others seen, and still somewhat green toward the tip. Sprout is a favorite pet of Gramble, who not only keeps it safe within a ball, but constructs elaborate obstacle courses for it. Gramble entrusts the player with Sprout because he believes it longs for adventure, which he wouldn't be able to provide himself.
At the end of the game, when Snaxburg is under attack by Bugsnax, the Buggy Ball is one of the tools Snorpy has redesigned for combat. It now has spikes on its exterior, which Gramble is not happy about. This enhanced Buggy Ball is used to defend Gramble and Wiggle from approaching Peelbugs and Crapples. Sprout behaves just as it does normally, and continues to follow the laser pointer, now destroying Bugsnax it comes into contact with.
Sprout is among the only Bugsnax that are not hostile during this time (along with two Kweebles), and it in fact helps the Grumpuses fight off other Bugsnax. It is unknown why this is, or if it is even aware of what is happening. Sprout's fate is ultimately unknown, as it is left in the ruins of Snaxburg when the Grumpuses escape. It can be either assumed that he died or survived.
- The audio bankfiles refer to the ball as "Stramble"