Water pistol

A water pistol was an Earth-made toy. They were often designed in the shape of human firearms, and were usually made of plastic. Each water pistol required water in the barrel, which was later squirted out by pulling a trigger. However, the range of which the water was squirted out was limited.

The Tenth Doctor found a water pistol in his pockets while looking for his sonic screwdriver. (COMIC: The Germ War)

While visiting Pompeii on 24 August 79 AD, the Tenth Doctor used a water pistol to hold the High Priestess of the Sibylline Sisterhood, who was a halfway stage between human and Pyrovile, at "gunpoint" to gather information from her. Knowing actual guns weren't invented at that period, he was able to get away with the fact that the High Priestess believed it was a dangerous weapon, until Sister Spurrina looked into his mind and called his bluff. However, squirting the toy at the High Priestess still caused it to feel pain, since water was the Pyroviles' weakness. He later used it again on an adult Pyrovile inside Vesuvius, causing a similar effect. The water pistol was shaped like a Walther P38, a German firearm from World War 2. (TV: The Fires of Pompeii)

The Tenth Doctor used a water pistol to find the rear entrance to the Temple of Kol-Ne-Wah. (COMIC: Final Sacrifice)

In 2008, Royal Albert Hall was briefly invaded by a Graske armed with a water pistol he had stolen from the Tenth Doctor. (TV: Music of the Spheres)

Amy Pond pointed a water pistol at the Eleventh Doctor when he visited her home at Christmas 2013, thinking he was a caroller. (TV: The Doctor, the Widow and the Wardrobe)

When the War Doctor met the Tenth and Eleventh Doctors in Elizabethan England, he griped at his future incarnations for brandishing their sonic screwdrivers as if they were water pistols. (TV: The Day of the Doctor)

Behind the scenes

 * In the 1960s, Dr. Who's Anti-Dalek Fluid Neutraliser was released; it was a simple water pistol.