Stal

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The Stal is a denizen of the Dark World in A Link to the Past. This skull-like enemy usually blends in with its surroundings (regular skulls that can be tossed around), and will flash and begin pursuit if it senses a disturbance next to it. Stals have also been known to hide under tall grass in search of prey, although this is an uncommon case. The Stal will actively follow and hunt its victim unless the victim can run away from it or destroy it with such weapons as a sword.

Stal- in Hylian Grammar
Stal- can also be used as a prefix added to a word to indicate it is a living skeleton of a creature. This can be confirmed by looking at most of the Stal- variations in Hyrule such as the Stalfos, Stalchildren, Stals, Stallord, etc. The only exception for this is the Skullfish, and Bubbles.