He was voiced by Tim Curry.
He tries to find a new place to spread his deadly infection into Frank since there are too many germs coming in because of Frank's poor diet and health, thanks to Frank resuming his poor eating habits. He was later confronted by Ozzy and Drix and tried to escape through his car. During their fight, a mosquito sucked them and brought them to the body of a cuban-american teenager named Hector Cruz. Scarlet was pleased and decides to infect Hector since Scarlet Fever is deadlier to kids than adults.
He begins sucking kidney fluids and gets mutated and more malignant. Scarlet starts a big inflammation and decides to finish his job at the heart which would kill Hector. However, Ozzy came and fought Scarlet in the helicopter. They were heading to the spleen which is a giant fan sucking bacteria. Scarlet was killed by the spleen while Ozzy escaped. Scarlet's last enzymes became harmless and went into Hector's blood for nutrients.