Escari is an advanced Scar capable of speech and intelligent thought.
Normally Scars have no personality and are just part of the hive mind. This is not the case for Escari, who are individuals with unique thoughts and ambitions that are thought to lead to Scar power struggles. These disputes make Escari eager to augment and improve themselves as they see fit.
Escari appears when enough Scars get together and reach a "critical mass".