Surprise! Only one, exactly correct answer! It is —- 
Bottle with top half upside down inside the bottom half. Two parts are screwed together to make a bottle. Dan Mottola
Giz Wiz: I bought mine at Deal Genius. Described as: Convertible 32oz Water Bottle – Compact for Travel, Hiking, Gym. Bottle unscrews and turns into drinking cup. (They fail to mention: make sure the liquid is below the ½ point before unscrewing!)
It was still available 12-31-22 for $4 + $5 shipping. https://tinyurl.com/24f3e9pe
And this answer was on the right track, so we picked it as a winner too.
This looks like an upcycled bottle that was turned into a drinking cup. Jeff Schulze
See instructions below ‘Cute, Clever, Could be’ answers below on how to get your prize
