Incorporeal Movement. The thought eater can move through other creatures and objects as if they were difficult terrain. It takes 1d10 force damage if it ends its turn inside an object.

Extra Sensory Perception. The thought eater detects strong sources of psychic power, strong potential arcane power and high levels of intelligence anywhere within 240 feet of itself as it drifts within the border ethereal boundary zone. Thought eaters can sense thoughts but they are not intelligent enough to understand them and have no capacity for language of their own.

Consume Magic. If a thought eater gets within 10 feet of an ongoing magical effect or condition, they are able to slowly drain its power, the spell can make a saving throw, the DC is 10 minus the level of the spell, but the DC increases by 1 point per round until eventually the thought eater drains enough magic to cause the effect to be dispelled.

Ethereal Invisibility. The thought eater is invisible while it remains within the border ethereal plane. It can move into the material plane fully as a movement action, but will not do so unless it is facing certain death on the ethereal plane. 

Psychic Drain. As an attack action, the thought eater targets one source of psychic or magical power or a being of high intelligence within 60 feet of itself. The target must make a DC 14 Intelligence saving throw or lose one psychic power point, or one spell slot (starting from the highest level and working down to lowest) or one point of intelligence. If the target's intelligence drops to zero, it dies. The thought eater will always drain psychic power first, arcane power second or resort to draining intelligence, and it will feed on the target until either the target dies, escapes or the thought eater is scared off by something that has detected its presence.