Plane ones.
or
they always take things literally.
or
One is a blood-sucking parasite, the other is an insect.
or
Billllyuns and billllyuns. Light bulbs are part of the interstellar "goo" that pervades our universe; they are star stuff.
or
What a turtle disaster
or
The players dribble a lot.
or
One; after reflecting in the twilight on the merit of the previous bulb.
or