Lluwen, Exchange Student // Pest Friend Honestly, just build a cycling deck, keep maybe five to ten creatures around that actually care about instants and sorceries, and go to town casting Pest Friend over and over
This black dinosaur can be especially powerful in a deck built around -1/-1 counters, as many of your opponents' creatures wont be able to block
One of my favorites is the Crypt Ghast thing, where you make all your lands tap for more than they should, or the Cabal Coffers thing, where you have some way of generating a bunch of mana using some specific combination of cards
So, lets say you cast Phantasmal Image and you copy your opponents Boros Reckoner
Go in expecting the typical box (1 SR + 3 ARs) and youll always be satisfied
Kastral, The Windcrested With Choco, it's very possible you may be forced to put your best Bird cards into the graveyard