Stage 4 Partial Transformation - "Unstoppable Mutation" (4단계 의태 - 살을 찢고 나온 돌연변이) is the name of the Venti's stage four Canine Partial Transformation. This canine transformation form will transform Venti's right arm into a blue head with red teeth, from his elbow to his fingers. The blue head has several coloured eyes that give the transformation a mutated look.
Venti achieved this transformation through the help of Khun Aguero Agnis's fiery sweetfish, which meant when Khun withdrew his power he lost this transformation. Venti was also able to use this transformation simultaneously with Sharp Gray Flesh-Piercing Spike.