trick golf balls

My son just purchased a trick gold ball.
It seems to go in a circle when you hit it.
How is this accomplished?
Whats inside?

It’s easy to trick golf balls.

They’re very dense.

Are we talking about putting or driving; if the former, it probably contains an off-centre weight, or maybe it isn’t actually perfectly spherical. If the latter, I don’t know, unless it could be something clever to do with the pattern of dimples, which affect the trajectory.