Thardus is a giant creature made of rocks. The only thing that holds Thardus together is Phazon. Being only rocks Thardus has no internal organs and is simply rocks binded by the Phazon energy and radiation. Thardus does have one rock where all the Phazon is stored but it can only be seen on the Thermal Spectrum. If Thardus becomes severely injured it will try to absorb Phazon around its surroundings usually picking up more rocks and kicking up a dust storm.

Since Thardus has no need to eat or sleep all its attacks are to attack enemies. Thardus' main attack is to throw rocks using Phazon and a strange kind of Telepathy to move the rocks toward its target. Another move is Thardus curls into a ball and rolls along the terrain crushing anything in its path. Once Thardus can't keep itself stable anymore all the Phazon destroys the creatures body.