Don't Drink the Water

Don't Drink the Water is the forty-second episode of Ben 10.

Plot
Growing weak with old age, Hex is seeking out something to make him stay young. So he goes to an old man asking him if he had anything that could make him young. The old man gives the water from the Fountain of Youth to Hex and he becomes a little younger. At the same time, Grandpa Max is having difficulties with his aging body, so he decides to impress Gwen and Ben at a fair to show them he's not as elderly as he seems. At the dunking game, Max challenges them to dunk him, to which Ben successfully does so.

But before they can get him out of the water, Hex attacks, splitting up Ben and Gwen in the process. During the battle, the water barrel Max was in earlier was destroyed, soaking Cannonbolt in the process. All sides are unaware that the water is from the Fountain of Youth. Max shrinks into a ten-year-old while Ben becomes a four-year-old. The booth's owner Hector is then targeted by Hex only to fight Ben as Hector escapes. They arrive at Hector's farm. While Ben tries to destroy the machine as Wildpup (thanks to the Fountain of Youth), they find Hector tied up as Hex managed to force him into revealing the location of the fountain. It turns out Hector is the guardian of the fountain, having been charged to do so by Juan Ponce de León 400 years ago.

When the group catches up to Hex, he mentions his plans to use the Fountain of Youth to become immortal. However, thanks to some taunting/hinting from Gwen, Ben uses Heatblast to vaporize the fountain (all the while throwing a temper tantrum), in the process exposing Hex to enough of the water to turn him into an infant. With the fountain gone, Hector reveals that the effects of the water will wear off without constant exposure. Meanwhile, Charmcaster finds her infant uncle Hex and enjoys taunting him at his expense. In the end Ben and Max have returned to their rightful ages.

Spells Used

 * Meta Quinix - Causes something to be lifted in air while being covered in a red aura.
 * Kellecki Erock - Causes rock spikes to erupt underneath the target.
 * Retoff Alegoria - Causes something to go flying at the enemy.
 * Teewat Legora - Creates a silver-colored whirlwind that attacks the target.

Characters

 * Ben Tennyson (10 and 4 years old)
 * Gwen Tennyson
 * Max Tennyson (60 and 10)
 * Hector
 * Mr. Zu
 * Charmcaster (seen at the end of the episode)

Villains

 * Hex

Aliens Used

 * Cannonbolt
 * Young Four Arms
 * Young Wildmutt (Wildpup)
 * Young Stinkfly (Stinkyfly)
 * Young Heatblast

Errors

 * After Hex threw Hector, background is changing. Also, after Ben turns into Cannonbolt, water and broken glass disappear.
 * Parts of the device used to analyze the water are changing.

Trivia

 * It is revealed that Grandpa Max has to wear reading glasses when he's reading small print.