the eggbug we put in pokeyman blue special cohost edition was specified in the pokeydex as being 13 feet and 12 inches tall
…according to these numbers, and should shoot upwards like a ping-pong ball at the bottom of the ocean.
But! That’s assuming 6.9 lb is eggbug’s true mass! If the 6.9 lb comes from standing on a kitchen scale, it means eggbug is slightly heavier than air, enough so to result in 6.9 lb of downwards force. This implies eggbug is cheerfully buoyant, and can bound along in great slow bounces like a giant beach ball with legs.
Worryingly, if eggbug’s mass and volume are constant and do not vary with ambient conditions, on a cold winter day, when the air is heavier, eggbug might float away…
6.9 lb is its weight -- the force it exerts on a scale due to gravity after accounting for buoyancy -- measured at sea level on a warm day, both of which are easy to find at its nesting grounds on the eastern shore of Cinnabar. 
(the effect of denser air on poke-eggbug is addressed in its gen 2 dex entry)
