This is book number 9 in the Stink series.
Sleepy, Sleepier, Sleepiest--NOT
When Stink's parents win tickets to an aquarium sleepover for the whole family, could it be science-freak Stink's dream come true or his worst nightmare? He loves learning about sharks, but does he want to sleep in the same room with them? He's nuts about gross stuff, but does he want go to bed thinking about the eating habits of the vampire squid?
Creepy, creepier, creepiest--yikes