Eddie Van Blundht (played by Darin Morgan) was a janitor working for Dr. Alton Pugh in West Virginia who had been born with a tail, a common genetic trait in his family. He also possessed a bizarre amount of muscle tissue under the skin around his entire body, allowing him to alter his appearance at will. During high school, he dated Amanda Nelligan and the two of them frequently went to see Star Wars. Van Blundht's father was known as Eddie the Monkey Man and performed in a circus, a life Van Blundht didn't want and had his tail surgically removed. Upon the death of his father, Van Blundht preserved the body with quick-lime and kept the corpse in his attic so as not to stop drawing his father's old age pension.
Van Blundht worked at a fertility clinic where he often saw women frustrated with their husbands. Van Blundht took it upon himself to help them out by taking on their husbands' appearance and impregnating them. Thus, five children were born over three months with the distinctive tail. Mulder and Scully were prompted to investigate after Amanda Nelligan claimed the father of her daughter came from "another planet." The father was not, however, alien, but rather it was Van Blundht in the guise of Luke Skywalker from Star Wars. Mulder nabbed Van Blundht upon discovering the scar where his tail had been removed while he was working on a sink. Van Blundht was taken into custody but escaped after striking a security guard over the head. Van Blundht would elude capture again while speaking to the agents in the image of his father. After his second escape, Mulder discovered the corpse of Eddie the Monkey Man.
Soon after, Van Blundht took on Mulder's appearance and visited Nelligan in the hospital. Thinking it was Mulder, she told him about Eddie and how she dated him in high school, even though he was a loser. "Mulder" gave her a rose and congratulated her on the birth of her daughter, which was especially confusing when the real Mulder showed up minutes later. Realizing Van Blundht was using his appearance, Mulder pursued him but was hurt and imprisoned in the recesses of a maintenance room.
While still in Mulder's appearance, Van Blundht accompanied Scully back to Washington, D.C. to present their investigative report to Skinner. Skinner was not impressed with the report and unnerved that "Mulder" had misspelled "Federal Bureau of Investigation" twice. Nevertheless, Scully and Skinner were unaware that anything was otherwise amiss. Van Blundht began snooping around Mulder's office and came to the opinion that the man, while good-looking, was a nutcase. Things did not improve when Van Blundht arrived at Mulder's apartment and was greeted with telephone messages from The Lone Gunmen and another of a more kinky nature. Determined to make the most of his situation, Van Blundht bought some wine and headed over to Scully's apartment.
Scully was surprised to see "Mulder," who said they never actually talked. Nevertheless, he and Scully finished off the wine while exchanging stories. As Van Blundht moved in to kiss Scully, the real Mulder - having escaped his prison - burst in to discover them. Scully realized what was happening and quickly withdrew in shock (at having nearly kissed Van Blundht) and embarrassment (at having nearly given in to an unspoken attraction to Mulder). Van Blundht surrendered and was committed to a psychological institution.
Mulder met Van Blundht one more time at the institution, where he was undergoing self-esteem therapy, including a cap labeled "Superstar!" that Van Blundht said other inmates would steal after beating him up. He was also given a drug that inhibited his shape-shifting. Before Mulder left, Van Blundht said he was born a loser, but Fox had chosen to be one, and told him to live a little and enjoy life more.
Van Blundht was annoyed by constantly reminding people of the silent "h" in his last name.