Someone who stays up wondering if there is a dog.
A watchdog.
The roof is on fire.
A flat fish !
A pugilist!
A teabag stays in the cup longer
Crossfit
A person who stays up all night wondering if there is a dog.
Staying up all night wondering if there really is a dog.
A guy who is up all night wondering if there is a dog.
A person who stays up all night wondering whether or not there is a dog.