Loox is bipedal and has two horns on the top of his head, a large eye on his face, and teeth under his eye.
Loox does not like it when people pick on him, though is also a bit hypocritical in that he also picks on other people (as suggested by flavor text when encountering a Loox and another enemy.) His description in the True Pacifist Ending Credits implies that he is less of a bully, and a "reformed bully" if the protagonist does not pick on him.
- Loox makes three small spheres appear from either side of the Bullet Board, which move and bounce around the board while slowly gaining speed.
- After Picking On, five spheres will appear instead of 3 and will be faster than normal.
- Loox makes several small sphere-worms appear from either side of the Bullet Board, which wiggle their way forward and disappear when hitting the edge of the Bullet Board.
- After Picking On, these sphere-worms become more abundant and will be faster than normal.
- Choosing "Don't Pick On" allows the protagonist to spare this monster.
- Picking on him does not allow the protagonist to spare him, but it awards five extra EXP. Before the latest patch, this would stack infinitely, allowing thousands of EXP to be gained from a single kill. However, it now only stacks up to 3, allowing a maximum of 22 EXP. This can be used to get extra EXP and thus making upcoming battles easier.
- However, when picking on Loox, his attacks become intense, making the battle harder.
- Please don't pick on me. [Neutral, first turn]
- Quit staring at me. [Neutral]
- I've got my eye on you. [Neutral]
- How about a staring contest? [Neutral]
- Don't point that at me. [Neutral]
- What an eyesore. [Neutral]
- You rude little snipe! [Pick On]
- Finally someone gets it. [Don't Pick On]
- Don't pick on him. Family name: Eyewalker. [Check]
- Loox drew near! [Encounter]
- A pair of Loox decided to pick on you! [Encounter with another Loox]
- Vegetoid and Loox attacked! [Encounter with Vegetoid]
- Loox and co. decided to pick on you! [Encounter with Vegetoid and Migosp]
- Loox is staring right through you. [Neutral]
- Loox is gazing at you. [Neutral]
- Loox gnashes its teeth. [Neutral]
- Smells like eyedrops. [Neutral]
- Loox is watering. [Low HP]
- "Loox" is a corruption of looks. Both his first and last names allude to his single prominent eye. His full name, Loox Eyewalker, is a pun that references Luke Skywalker, a prominent character from the Star Wars franchise.
- Loox's quote "Please don't pick on me" may be a reference to the Pumpkin-Head Ghost boss from the game Monster Party, who says this exact quote immediately before attacking. It may also be in reference to one of the final bosses in the Earthbound Halloween Hack, also developed by Toby Fox. One of the lines that Id spouts out is "QUIT PICKING ON ME!", which is similar to the well-known phrase that Loox likes to throw.
- A Loox replaces the Boss Monster next to the human in the Undertale Demo intro sequence and the intro played before Photoshop Flowey's battle.
- His appearance resembles Mike Wazowski from Monsters, Inc. and the Ahriman from the Final Fantasy series.
- There is an NPC in the Snowdin Library that appears to be a female Loox.