Bowling ball
The bowling ball was the main piece of equipment used in the game of bowling. They were hurled across a bowling alley, with the intention of hitting as many pins as possible. They came in many colours, (TV: Day One, PROSE: The Quantum Archangel) and had three ridges on them to facilitate holding them. (PROSE: The Gods of the Underworld, Wetworld) These balls were considered large, and could easily breaks through wooden doors if thrown at them. (PROSE: The Monsters Inside, Beltempest)
Bernice Summerfield hypothesised that a Mayan temple might have "granite bowling balls flung by anvils landing on a see-saw and bouncing off a baby trampoline". She claimed to be really looking forward to this, and was mildly disappointed when they encountered no such difficulties. (PROSE: Sky Pirates!)
River Song described Max Kliener as a "human bowling-ball" after seeing Rock Railton knock him over in his haste to leave a restaurant. (PROSE: The Angel's Kiss) Monica Jeffries compared the N-Forms ravaging the Earth to bowling balls, knocking over everything in their path. (PROSE: Damaged Goods) Clarence was too described as a bowling ball when he sent half a dozen people "flying off to their feet". (PROSE: Twilight of the Gods)
Bill described Ray's head as "a shiny pink bowling ball". (PROSE: Mordieu)
Bernice Summerfield felt as if "someone had stuck pudgy digits in her eyes and mouth and had been using her head for a bowling ball" after gaining a huge headache from the noise the New Dawn's engines made in a crash-landing. (PROSE: The Gods of the Underworld)