Teacup, Swiftstep Pickpocket

Haste, skulk (This creature can't be blocked by creatures with greater power.)
Pickpocket 3 (Whenever this creature deals combat damage to a player, reveal the top card
of that player's library. If it's a nonland card
with mana value 3 or less, you may cast it
without paying that card's mana cost.)
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https://mtgcardsmith.com/user/Teacup
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Easter Egg challenge -
Create a card that allows you to cast spells that you don't own.