Villain(s)  Invisible man

Actor(s):  Bud Abbott, Lou Costello, Nancy Guild, Arthur Franz

Brief Description  Released in March 1951 and directed by Charles Lamont, Abbott and Costello Meet the Invisible Man stars Bud Abbott as Bud Alexander and Lou Costello as Lou Francis. Fresh out of detective school, the bumbling duo is hired by Tommy Nelson, a boxer framed for his manager's murder, who injects himself with an invisibility serum to evade the police. The movie blends slapstick humor, classic Universal monster lore, and a boxing gangster subplot.

Plot:
Bud and Lou graduate from a private detective school and set up their new agency. Their very first client is Tommy Nelson, a boxer who has just escaped from prison. Tommy maintains his innocence, claiming he was framed for murdering his manager because he refused to throw a fight. He hires the duo to help him sneak out to the laboratory of his fiancée’s uncle, Dr. Gray. When the police arrive at the lab, a desperate Tommy injects himself with Dr. Gray's highly volatile invisibility serum to avoid capture. Dr. Gray is horrified because the formula is unstable and gradually drives the user insane. Now completely invisible, Tommy convinces Bud and Lou to help him uncover the real killer.

To infiltrate the crooked boxing syndicate run by the gangster Morgan, Lou goes undercover as a boxer named "Lou the Looper," with Bud acting as his manager. Morgan tries to fix Lou’s upcoming fight, ordering him to take a dive. Instead, during the hilariously chaotic boxing match, the invisible Tommy stands in the ring alongside Lou. Tommy punches the opponent and moves Lou out of harm's way, leading Lou to an unexpected and bizarre victory. Morgan’s thugs get suspicious and target the detectives. In a final showdown at a laboratory and a hospital, the invisible Tommy manages to subdue the villains and clear his name. However, Tommy is severely wounded during the chaos. At the hospital, he receives a blood transfusion from Lou. The transfusion saves Tommy's life and restores his visibility, but it temporarily causes Lou to turn invisible—leading to one final comedic gag.

The ring scene where Lou knocks out a professional boxer with the help of invisible punches is widely considered one of the funniest physical comedy routines in Abbott and Costello's filmography. The script was originally written as a serious installment for the Invisible Man franchise titled The Invisible Man Strikes Back. Following the massive success of Abbott and Costello Meet Frankenstein (1948), it was rewritten into a horror-comedy. A photograph of the original serum inventor, Dr. John Griffin, appears in Dr. Gray's lab. The photo is actually of actor Claude Rains, who famously played the titular character in the original 1933 classic, The Invisible man.