The Elevator (The Twilight Zone)

Plot

Late at night, two brothers, Will and Roger, arrive at a closed factory in search of their missing father, who is undertaking secret experiments there designed to solve world hunger. Though the elder brother, Roger, is skeptical of his father, the younger brother, Will, defends him.

Upon entering the building, they follow a set of footprints in the dust to a room that Will was warned never to enter. Going inside, they find a trail of gigantic dead rats, each larger than the last, followed by the bodies of a house cat and a dog, both also of enormous size. Roger begins to put things together and believes that whatever food their father created must have increased the size of the dead animals once they ate it. So anything that eats this super food will do the same. Will turns on the lights to see a mass of white strands in one corner that apparently are pure protein.

Concluding that something even larger killed the cat and the dog, the two brothers follow the footsteps to an old elevator that invokes nostalgic memories. Roger thinks that the elevator doesn't work anymore, but then it starts to come down. When it reaches the ground, however, the doors open to reveal a huge spider that had grown due to the effects of their father's experiment, but was much larger than all of the other dead animals. It snatches them and takes them upward into the dark, while both are screaming and struggling to try to get free. When the elevator reaches the top, the screaming stops and one of their flashlights drop to the bottom of the shaft, its lens cracked from when it hit the ground. Blood then drips onto the floor below, implying that the spider has killed and devoured Will and Roger.