The clearish red substance that exits the ketchup bottle if the bottle is not shaken. This substance is sweat from the tomatoes being kept in such close quarters, and often ruins hamburgers.
Bitchy customer- "Ummm, WAITER! This ketchup bottle just leaked watery stuff onto my sandwich. I want a new meal"
Waiter- "No, you dumb cunt- thats ketchup sweat. Enjoy!"
(5 minutes later)
Waiter- "How does it taste...?"