Polymorphous Rush

The creature that's copied isn't targeted by Polymorphous Rush. You choose that creature as the spell resolves. It can be one of the targeted creatures. A creature can become a copy of itself this way, though this usually won't have any noticeable effect.

You choose how many targets each spell with a strive ability has and what those targets are as you cast it. It's legal to cast such a spell with no targets, although this is rarely a good idea. You can't choose the same target more than once for a single strive spell.

If such a spell is copied, and the effect that copies the spell allows a player to choose new targets for the copy, the number of targets can't be changed. The player may change any number of the targets, including all of them or none of them. If, for one of the targets, the player can't choose a new legal target, then it remains unchanged (even if the current target is illegal).