CURIE

Can confirm. It's 999.9kg. Which is the same weight but in metric.

People are hand-waving this by going "it's just constantly floating in her bag and Lillie is only pulling it along."

I'm not even sure if that would actually be possible, but it's the only real explanation I've seen for why Lillie's bag can even hold it without getting the bottom ripped open.

Even if it were using psychic powers to ignore gravity, she'd have to apply enough force to move it horizontally.  Either way you look at it she's a superhuman with a superhuman bag.  Besides, if it floats there and has no weight then how does the Pokedex calculate said weight?
 

I hope Ash ends up holding it at some point when the anime gets that far.

if ash holds it theres going to be an uproar. But for now hes holding litten tomorrow