Silver Rock are enemies from Kingdom Hearts II.
Bearing close resemblance to its predecessors, a Silver Rock is a type of magic-using Heartless named after its color and a form of music. Despite the name "silver," Silver Rock are the white member of the family. They utilize balls of energy and light as weapons, and can teleport.
Rock is a style of music characterized by basic drum-beat, generally 4/4 riffs, based on (usually electric) guitar, bass guitar, drums, and vocals.
It quickly disappears into a ball of light, setting off an explosion when it re-appears. Use reaction commands when it's in light form. It easily resists magic, so don't be shy about using the Keyblade!