Talk:Mewtwo VS ???/@comment-25620113-20160609111341/@comment-24281142-20160609171541

It's confirmed he's not catching something new, and bringing back a Pokemon is highly unlikely.

My bets are that he either has the guy from the marshlands sends him Goodra's Pokeball (which makes sense, given how close the league is to this episode) or Ash uses Squishy (which would be weird but hype all the same).