Aboleth

Armor Class 17
Speed 10 ft., swim 40 ft.
STR 21 (+5) DEX 9 (-1) CON 15 (+2)
INT 18 (+4) WIS 15 (+2) CHA 18 (+4)
Multiattack. The aboleth makes three tentacle attacks.
Tentacle +9 hit, 10 ft. reach, one target. 12 (2d6 + 5) bludgeoning