Your attack summons thorny vines that possibly Ensnare your target.
Ensnared creatures cannot move and take 1d6Piercing damage at the start of each turn. An ally can use their Help action to try and tear away the vines.
↑Fist Gai's full name is still listed in the game files for his dialogue: Click on /Qui Gai/ - S_WYR_WyrmRock_SouthBridgeGuard_003 7a5a9b6d-2200-431e-a41f-bfddef7cd45c - (-1; 42; 179)