A Curious Fossil Rock is a fossil rock that has to be cleaned on both sides. Vivosaur fossils found in these rocks are usually ammonites or other small prehistoric sea creatures. These fossil rocks have only appeared in Fossil Fighters: Champions thus far.
There are no Buster Points in curious fossil rocks. To facilitate and/or expeciating the cleaning process, the player may upgrade their tools, team up with a friend, or simply use Time Pluses to comfortably extend the clock.
Occasionally, players can obtain dropping fossils by cleaning curious fossil rocks.