Says me!
and Sez me!Inf. a formulaic answer to Says who? Tom: Says who? Fred: Says me, that's who! Tom: You? Fred: You got it, buster. Says me!
Says who?
and Sez who?Inf. a formulaic challenge indicating disagreement with someone who has said something. Tom: Says who? Fred: Says me, that's who! She drew herself up to her full height, looked him straight in the eye, and said, "Says who?"