They had a line of plastic balls with the Xtreme name. They were an offshoot from the BOOGIE line of plastic balls, and picked up the Xtreme tag when they ran some with wilder colors and called them BOOGIE EXTREME, which was later shortened to take the E off the extreme term, and then later the boogie was also removed, leaving them with the name XTREME. It went like this:
1st was BOOGIE
2nd was BOOGIE EXTREME
3rd was BOOGIE XTREME
4th was XTREME
SO, if it is one of those, it is just a plastic ball with a pancake in it.