"You can't know what it does unless you drink it."
"I'm not drinking it."
"It's your turn, I drank the last one."
"You dumped it down the toilet."
"Good thing, too. It blew out the plumming."
"I'm still not drinking it."
"What if it makes you invincible?"
"I expect it won't do anything but make me heavier."
"So drink it already, you chicken."
He swigged the whole bottle, and let out a belch.
"I don't even feel heavier."
"All that money for a heavy water potion, and it's just water?"
"I think someone's going to be giving us our money back."
They left in the general direction of the market.
Combining science fiction with fantasy doesn't always have interesting results.