The Harlequin Beetle is a large beetle characterized by its long forelegs. The forelegs size depends on the gender. For females, the legs are typically around the same length of their body. However for males, their legs can reach lengths twice that of their body (I would go with a female one for the game lol). The forelegs are typically used by males to flip other Harlequin beetles to find a mate.
Concept 1: Handles
This concept would have medium strength, not much flying, but be quick on the ground. The low flying speed is because trying to glide into a steal is hard enough; If an opponent tries to air steal from a harlequin and they just move the ball, it's unrecoverable for the stealer and they need to ascend again by no fault of their own.
The on-ball and off-ball are the same ability, simply extending or retracting the forelegs on a cooldown. While the forelegs are extended, the beetle cannot headbutt, regardless of ball possession. Extending the legs is quick but retracting them is slower, this gives enemies some time to react before the beetle presumably headbutts the ball after retracting. The idea is that while the beetle runs on the ground, it can quickly move the ball away from enemies trying to steal it. The larger distance from the ball also makes turning more powerful, as the ball is offset much further.
One concern that comes to mind is a player extending while holding a ball and then rapidly spinning to avoid the ball being stolen, but headbutting the beetle would make them lose it anyways so it's likely a non-issue.