Caustic gazer

The Caustic gazer is encountered during the Salt in the Wound quest. During the quest, the stalker blocks you from getting to the Seeker of Truth. Thus you must "tank" it, and choose one of your team mates in the quest (Kennith, Ezekial, or Eva) to get the Seeker gland to make the anti mind control serum. It looks exactly like a Seeker, only greenish.