Hilarious things you've found in RAW?

[ShurikVch]

Maybe it's made of pumice? Sure, the creation instructions say it's made from "hard stone, such as granite", but it also requires polymorph any object.

Checked the article in the Epic Level Handbook: actually, it weighs "only" 250,000 pounds, and 40'x40'x70'
With 112,000 cubic feet and 250,000 pounds - it's denser than Osmium (over x1.5)

The ability to float is about displacement, not weight.

Yes, I know.

To be a little gruesome it's why the average drowned person sinks, but when the body starts to decay it'll bloat and float. Swimming displaces water to move you or keep you afloat.

Actually, most persons are don't even sunk at all (alive or dead) - no efforts to stay afloat required
(But bloating corpses are occasionally even brought to the surface weights which their murderers used to "keep 'em down")

With enough strength, speed, endurance, and proper technique a 100ft by 1ft rod of lead with two 1in wings could probably float on air.

I doubt it - sounds like not enough leverage
But - if you have calculations, it would be interesting to check it...