can you tell me what is unique?

Can you tell me what is unique about all of these sentences?

(1)"Eva, can I stab bats in a cave?" (2)"Mr. Owl ate my metal worm." (3)"Was it a rat I saw?" (4)"A nut for a jar of tuna", (5)"Ma is as selfless as I am",(6) "Dammit, I'm mad!", and (7) "A Santa lived as a devil at NASA".