Vek Tabok, The Befouler is a unique Flesh Gorger in Act V of Diablo III. It is found in the Passage to Corvus, specifically the real passage, not a false one.
In combat, it has the Desecrator, Vortex and Fast traits.
A bounty may be offered to kill Vek Tabok, in which case the secondary objective is to kill 150 enemies.