獨眼（Loox）is a bipedal Monster with two horns on the top of his head, a large eye on his face, and teeth under his eye.
獨眼（Loox）不喜欢 when people pick on him, though is also a bit hypocritical in that he also picks on other people (as suggested by his Flavor Text when encountering a Loox and other enemies). If the protagonist picks on him, he will call them a "rude little snipe." 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.
- 獨眼（Loox）makes three small spheres appear from either side of the 彈幕面板, 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.
- 獨眼（Loox）makes several small sphere-worms appear from either side of the Bullet Board, which wiggle their way forwards and disappear when they hit an edge of the box.
- After Picking On, these sphere-worms will be much 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. Because of this, it is suggested to attack Loox until one hit kills him.
- "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 reference to 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 asks the protagonist not to pick on them immediately before attacking.
- 獨眼（Loox） replaces the Boss Monster next to the human in the Undertale Demo intro sequence and the mock intro played before the Neutral Ending final boss.
- 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 Loox.
|主要角色||花花 ● Toriel ● Sans ● Papyrus ● Undyne ● Alphys ● Mettaton ● Asgore Dreemurr ● Frisk ● Chara|
|廢墟的敵人|| 假人 ● 青蟈 ● 胡思 ● 小霉 ● 獨眼 ● 菜菜 ● 否音 ● 鬼鬼 |
歐防風 (困難模式) ● 霉德莎 (困難模式) ● 弗音 (困難模式)
|雪町的敵人||雪鴨 ● 寒鴨 ● 冰帽 ● 禮鹿 ● 躲狗 ● 公狗狗和母狗狗 ● 小狗狗 ● 大狗狗 ● 傑利 ● Glyde|
|瀑布的敵人||亞倫 ● 大霉 ● 約涮 ● Temmie ● 憤怒假人 ● 羞壬|
|熱地的敵人||火金 ● 傲嬌飛機 ● 火榴繩 ● 瑪菲特 ● 皇家衛兵 ● 真抱歉|
|核心的敵人||終極青蟈 ● 胡思亂想 ● 散光 ● 怒法 ● 夜騎|
|真正的實驗室的敵人||合成怪物 (記憶之首 ● 內狌 ● 收割鳥 ● 檸檬麵包 ● 雪鴨的母親)|
|攤販、商人||Nice Cream傢伙 ● 雪町店長 ● Gerson ● Temmie商店 ● 鱷鱷和貓貓 ● 漢堡店員|
|其他角色||NPC們 ● 怪物小孩 ● 煩人的狗 ● 河流人 ● 八名人類 ● Asriel Dreemurr ● W. D. Gaster●|