S1·E21 Hog Hoops

A pig doctor treats a pig affected by measles, by using a stethoscope, a hammer for reflexes, and then giving them some medicine on a spoon, and the sick pig almost immediately became better. He does the same with the opera pig from "Piggy In the Middle", who has caught pneumonia. His third patient is the floating pig who swallowed the alien ship from the previous episode, "Abduction". He uses the stethoscope, but hears weird sounds. He tries the hammer, but it gets zapped into dust. He has the pig open his mouth, and then the alien ship flies out. The third pig feels better and leaves. The doctor, who believed he was having a mental breakdown, drank the whole bottle of medicine, then throws it away.