It's about 50,000 times as heavy as a Mouse
In other words, the weight of a Mouse is 0.0000210 times 999 kilograms.(a.k.a. "House mouse", Mus musculus) (adult)
The weight of a mouse is typically an average of 0.021 kilograms. While most mice typically live two to three years, the Methuselah Mouse Prize — an award administered by a non-profit organization which advances aging-related research — was once awarded to a team of scientists whose research resulted in a mouse living just under five years.
It's about 65,000 times as heavy as a Compact disc
It's about 85,000 times as heavy as a Battery (AAA)
In other words, the weight of a Battery (AAA) is 0.0000120 times 999 kilograms.(Alkaline)
An "AAA" size battery weighs 0.012 kilograms. Batteries are named by the American National Standards Institute (ANSI) Committee C18 and AAA batteries were given their name because they were smaller than the "AA" and "A" size batteries which were invented first.
It's about one-one-hundred-thousandth as heavy as The CN Tower
In other words, 999 kilograms is 0.00000847260 times the weight of The CN Tower, and the weight of The CN Tower is 118,030 times that amount.(a.k.a. La Tour CN, a.k.a. Canadian National Tower, a.k.a. Canada's National Tower) (Toronto, Canada)
The CN Tower weighs approximately 117,910,000 kilograms. The Tower is home to the world's highest glass floor — a viewing area that allows visitors to look straight down 342 m (1,120 ft) to the ground below.
It's about 150,000 times as heavy as an Eye (Human)
In other words, the weight of an Eye (Human) is 0.00000710 times 999 kilograms.(adult)
A fully developed eye (in a person over the age of thirteen), weighs about 0.0071 kilograms. The pupil of the eye varies depending on the amount of light it is exposed to, but typically measures about 4 mm across.
It's about 200,000 times as heavy as a Quarter
In other words, 999 kilograms is 176,200 times the weight of a Quarter, and the weight of a Quarter is 0.0000056750 times that amount.(United States quarter-dollar coin) (a.k.a. Quarter dollar, a.k.a. America the Beautiful quarter, a.k.a. two bits)
The America the Beautiful series quarters, which began to enter circulation in 2017, weigh 0.00567 kilograms each. In answer to the common riddle, there are 119 ridges around the edge of the coin in its current design.
It's about 200,000 times as heavy as a sheet of Paper
In other words, the weight of a sheet of Paper is 0.00000500 times 999 kilograms.(for US Letter, a.k.a. ANSI A; 215.9mm by 279.4mm (8.5 in x 11 in); 20lb)
The weight of a ream (500 sheets) of 9.10 kilograms, 8.5 inch x 11 inch paper is 2 kg, each sheet weighing 0.005 kilograms. Paper of this size has a thickness of 0.004 caliper (0.1 mm).