Paterkillers!

Mama:  Kay.  Lay down.  Do you want covers?
Miss A:  Covers.
Mama:  Miss A, what did we do today at the park?
Miss A:  Ummm.  Play swings!  And... paterkillers!!!  (Caterpillers.)
Mama:  Paterkillers?
Miss A:  And a big paterkiller, at Mary's house.
Mama:  A big paterkiller at Mary's house?  Wow, two paterkillers?  And then we saw another one on the tree, huh?  What else happened today?
Miss A:  A big horse.  (Holding a stuffed horse...)
Mama:  Yeah, the horse.
Miss A:  Nee-hee-hee!
Mama:  Okay.  Night night.