One is a blood-sucking parasite, the other is an insect.
or
A Broncosaurus or a Tyrannosaurus Tex.
or
A crookodile
or
To get to the other slide!
or
To prove he wasn't a chicken!
or
They're cheaper than day rates.
or
To visit the milky way.
or
C over lambda.
or
He presses the paws button.
or
None. They just steal somebody else's light.
or