My sister’s dog does this all the time- she’ll give you one toy, you throw it, and she comes back with a different one that she couldn’t find the first time around. And in case you’re wondering: The first several times Reanin threw the ball he threw it across land. Then he decided to throw it across the river, because Au likes to swim and he wanted to get some more energy out of her. She had a momentary lapse in memory and forgot that she likes swimming, swerved, and ran along the riverbank until she found a stick that she brought back. Then she ran into the water just fine.
minotaurgirl- I think it would just feed his conceit even more.
My dog does that occasionally too. He'll go crazy for one toy, and when I toss it if there's another toy (or one of my stuffed animals he's not allowed to chew up) in the vicinity, he'll end up going after it instead. Of course he's over twenty years old and going blind and deaf, so I can't really blame him-he probably can't see what it is he's supposed to be chasing.
....Maybe we should paint his nails pink then? With sparklies? That might take him down a peg or two.