False Eye
Looks like part of the groups eye space, but part of the surrounding stones can be put into atari forcing the opponent to close it.
https://senseis.xmp.net/?FalseEye
This tag gives a hint.
Created by igol326.
Other tags:
Diabolical, 2-1 point, Attack, Bamboo Joint, Belly Attachment Tesuji, Bent Four in the Corner, Bulky Five, Carpenter's Square, Clamp, Comb-Formation, Connect, Crane's Nest, Dame, Damezumari, Door Group, Double Atari, Double Ko, False Eye, Fuseki, Geta, Golden Chicken Standing on One Leg, Haengma, Hane, J-Group, Joseki, Ko, L+1 Group, L-Group, Ladder, Loose ladder, Miai, Monkey Jump, Moyo, Nakade, Nose Tesuji, Oiotoshi, Oshi-tsubushi, Patting the Raccoon's Belly, Placement, Rabbitty Six, Sabaki, Sacrifice, Seki, Semeai, Semeai Type 1, Semeai Type 2, Semeai Type 3, Semeai Type 4, Semeai Type 5, Semeai Type 6, Sente, Separate, Shimari, Snapback, Spiral Ladder, Squeeze , Superko, Symmetry, Tenuki, Throw-in, Tombstone, Tsumego, Under the Stones, Weak Carpenter's Square, Yose [Create new tag]