To assist with his work due to his failing eyesight, renowned biologist Dr. Alexander Thorkel (Albert Dekker) invites two prominent scientists and a mineralogist to his hidden Amazon jungle laboratory. Thorkel remains evasive about the nature of his experiments, and after the team evaluates his bacteria slides, he orders them away. When they refuse, Thorkel and his servant trick them into a chamber where Thorkel shrinks them down to microscopic size, and they escape to the terrifying jungle.

Hiram Stokely (Boris Karloff), a recently deceased man, discovers that he has only one day to enact a good deed in order to avoid eternal damnation. Hiram's scheming lawyer, Reginald Ripper (Basil Rathbone), is determined to get his fortune, and is willing to bump off potential heirs such as Chuck Phillips (Tommy Kirk) and Lili Morton (Deborah Walley) to achieve his goal. As Chuck, Lili and others have a lively pool party, Hiram recruits the ghost of his dead lover to help set things straight.

After a black hole strikes, it opens up another dimension in a rural Wisconsin town, and soon there is an invasion of gigantic arachnids who crave human flesh. NASA scientists Dr. Vance (Steve Brodie) and Dr. Jenny Langer (Barbara Hale) try their best to save humanity as a romance blooms between them. Meanwhile, local Dan Kester (Robert Easton) squabbles with his wife, Ev (Leslie Parrish), and has a dalliance with local bartender Helga (Christiane Schmidtmer).

A 16-year-old high school girl learns that she happens to be a descendant of one of the witches of Salem. She uses her newfound powers to snag herself the handsome football captain as her boyfriend.

An ageless submarine captain (Joseph Cotten) ferries three explorers to an underwater colony threatened by a villain (Cesar Romero).

When a white racist wakes up a head transplant, he learns that his head has been transplanted onto the body of a black convict.

Truckers in a convoy keep a CB lookout for women and stolen cars.

A New Orleans Gypsy queen (Nina Foch) tries to kill a couple (Stephen Crane, Osa Massen) who know she is a werewolf.

An aspiring reporter spends a night in a haunted mansion for a story. But what was supposed to be an open-and-shut case soon turns into a murder mystery when the elusive ghost plays a haunting tune.