Earth to Clunk

What do you send your alien pen pal Clunk to make it clear you do not want an alien pen pal? You send him your big sister. That'll teach Clunk to have a pen pal from Earth-or so our intrepid narrator thinks. But then Clunk sends him a Zoid, an exasperating Zoid that follows him everywhere. After swapping dirty socks, three Forps, some old lasagna, a weird glob, and a string of Christmas lights, our hero seems to be having . . . could it be . . . fun? But then: Clunk stops sending stuff. Oh ...