shapeshifter cards mtg Type: Creature, Subtype: Shapeshifter, 157 Escaped Shapeshifter has flying Rules Text: Changeling, Subtype: Shapeshifter,

They often care about stealing cards from other players and/or artifacts and Treasure tokens to flavorfully depict the plundering and valuable loot that these scallywags are all about

Problem #2 It causes inventory problems

That's 144 permutations to consider casting this in a pretty normal situation

If we preferred black instead, we might consider a Tezzeret the Schemer style of deck (obviously still using Karn), as Tezzeret is great for ramping into Karns Temporal Sundering and synergizes well with a lot of the same cards we might be interested in because of Karn

If you do, draw X cards, then you may put a permanent card with mana value X or less from your hand onto the battlefield, where X is the sacrificed creature's mana value