Ice armor is a Phrygisian invention, worn by Phrygisian individuals in combat as a source of protection from opponents. It is generated by the species' natural cryokinetic abilities over the individual's upper body. The ice armor is not particularly strong, especially in the neck, and can be easily ripped off the wearer with enough force.
The Bounty Hunter Rundas wore ice armor during his battle against Samus Aran in Metroid Prime 3: Corruption. The armor is his weak point in the battle. To defeat him, Samus must fire at him repeatedly until he becomes stunned. At this point, she can rip his armor off with her Grapple Lasso and attack his unprotected form.
It is possible to make Rundas become "stuck" in a wall in the Temple of Bryyo by ripping off his ice armor when he is very close to the wall. While stuck, Rundas will endlessly attempt to run out of the wall, meaning he cannot use his attacks and he is completely vulnerable. Firing missiles or ripping off his armor from a certain angle can free him.