Dr. Sebring was called by Martin's mother when she became concerned about Martin's constant mention of a centipede with twelve people. Dr. Sebring speculated that Martin might of been relating the pain a centipede bite can inflict along with its phallic shape to the sexual and psychological abuse he endured from his father. Despite this, he assured them there is nothing to worry about.
Despite his friendly nature, Dr. Sebring was just as corrupt as Martin's mother, prescribing heavy medication and touching him inappropriately. Since Sebring desired to have sex with Martin, he saw a prostitute by the name of Candy, who serviced him while he spoke to cab driver Paul. When Martin angrily shot Paul, startling Candy, Dr. Sebring confronted Martin who was in the mist of capturing parts for his human centipede. Dr. Sebring told Martin that what he was doing was wrong and asked him to hand him his gun. Martin then shot Dr. Sebring in the genitals and then the head, killing him.