Listen up, buttercup. This "joke" is like when your brain farts and you think you've created something profound, but it's just gas. A hefty dude tries to cheat the scale by sucking in his gut (newsflash: doesn't work, genius). A physicist tries to be a smart-aleck by bringing up the law of conservation of mass (big words for you, huh?). Then the big guy sits on the physicist, which somehow makes the physicist lose mass? I dunno, maybe you're not as dense as a neutron star, but you're definitely orbiting the stupid zone.