One has claws at the end of its paws and one has a pause at the end of its clause
or
When it's going cheep!
Did you hear the one about the crow and the telephone pole?
He wanted to make a long distance caw.
or
Can I have your hand, hand, hand, hand, hand, hand, hand, hand in marriage?
or
One is a blood-sucking parasite, the other is an insect.
or