An intellect devourer resembles a walking brain protected by a crusty covering and set on bestial clawed legs. This foul aberration feeds on the intelligence of sentient creatures, taking over a victim's body on behalf of its mind flayer masters.

Illithid Creations

Mind flayers breed intellect devourers to serve as roaming hunters of the Underdark, creating an intellect devourer by taking the brain of a thrall and subjecting it to a horrible ritual. As it sprouts legs, the brain becomes an intelligent predator as twisted and evil as its masters.

Deadly Puppet Masters

An intellect devourer consumes a creature's mind and memories, then turns the host body into a puppet under its control. An intellect devourer typically uses its puppet host to lure others into the domain of the mind flayers to be enthralled or consumed.