Treason at Cloud City

Put up to one target instant or sorcery card from your graveyard on top of your library. Amass Stormtrooper 2. (To amass Stormtrooper 2, put two +1/+1 counters on an Army you control. It’s also a Stormtrooper. If you don’t control an Army, create a 0/0 Stormtrooper Army creature token first.)