Thardus

Thardus is an enormous rock monster charged with phazon energy that inhabited Tallon IV in the Phendrana Drifts of the Overworld. It was originally an experiment by the Space Pirates to use phazon to create sentient creatures out of inanimate object, but was placed in the cavern found in the only game it appeared in, Metroid Prime.

Thardus controls the rocks in its domain and the icy weather that resides over the drifts. It can also launch an Ice Beam attack that is dodgeable by battling from one of the rock ledges around the arena, as well as rolling into a ball and launching itself at enemies. To defeat the behemoth, Samus must use the Thermal Visor to locate Thardus's weak spot, then fire at it with a weapon, preferably the Wave Beam. Once Samus hits the spot a few times, Thardus will release enormous thermal energy, making the visor "white out". She must than switch back to the Combat Visor and fire at the now-blue weak spot. Thardus will continually switch weak spots until the third weak spot is hit. Then it will unleash an ice storm, making it hard to see in the Combat Visor. Samus must continue the process, until the creature dies once the sixth weak spot is destroyed.