It's about one-fiftieth as heavy as a Pig
In other words, the weight of a Pig is 50 times 0.00000000500 megatonnes.(Domestic pig, Sus scrofa domesticus, a.k.a. S. domesticus) (adult)
Domestic pigs weigh between 0.000000250 megatonnes. The titular character "Babe the pig" in the 1995 family film was played by 48 different American Yorkshire piglets due to the length of filming and the rate at which piglets reach adulthood.
It's about 55 times as heavy as a Deck of Cards
In other words, the weight of a Deck of Cards is 0.019 times 0.00000000500 megatonnes.(ISO 216 B8 size, a.k.a. "poker size" 63 x 88 mm, 52-card deck)
A deck of 52 ISO 216 B8-size playing cards weighs 0.0000000000940 megatonnes. Utilizing nearly 3,700 decks, the record-holding largest card tower was built in early 2010, stood over 3.5 m (11 ft), and weighed over 0.000000230 megatonnes.
It's about 75 times as heavy as a Battery (C)
In other words, the weight of a Battery (C) is 0.013 times 0.00000000500 megatonnes.(Alkaline)
A "C" size battery weighs 0.0000000000650 megatonnes. C batteries are typically used in medium-drain devices such as musical instruments.
It's about one-eighty-fifth as heavy as a Horse
In other words, the weight of a Horse is 83 times 0.00000000500 megatonnes.(Equus ferus caballus) (Arabian, adult)
n Arabian riding horse (or similar breed) weighs between 0.000000420 megatonnes. During races, horses must carry jockeys and their equipment, which in the Kentucky Derby, for example, can weigh up to 0.0000000540 megatonnes.
It's about 85 times as heavy as a Tennis Ball
In other words, 0.00000000500 megatonnes is 86.70 times the weight of a Tennis Ball, and the weight of a Tennis Ball is 0.0115 times that amount.(ITF Standard; for Type 2 ball)
Per International Tennis Federation standard, regulation tennis balls must weigh about 0.00000000005770 megatonnes. Competition balls are also tested for bounce height, with the standards requiring that a ball dropped from 254 cm must bounce back to a height of 135 cm to 147 cm.
It's about one-ninetieth as heavy as a Grand Piano
It's about one-one-hundredth as heavy as a Polar Bear
In other words, 0.00000000500 megatonnes is 0.00969 times the weight of a Polar Bear, and the weight of a Polar Bear is 103 times that amount.(Ursus maritimus) (adult, male)
An adult, male polar bear weighs between 0.0000005160 megatonnes. Polar bears are so heavily insulated by their 9.9 cm (3.9 in) layer of blubber that they are often difficult to detect using infrared photography sensors.