Sakashima's Protege

The clone that arrives on your terms, not your opponent's. A conventional copy effect makes you tap out and duplicate whatever sits on the battlefield already, betting the target survives to your next window; this one flips the timing by keying off anything that entered this turn, yours or theirs, at flash speed. Cast it end-of-step to duplicate your best permanent, or hold it up as an ambush when an opponent slams a titan of their own. Cascade is the wrinkle that pays for the awkward six mana: a copy spell is often a dead draw in a topdeck war, but casting this triggers a free hit that advances your board a second time, so one card does the work of two. There is a subtler line hidden in the sequencing, too: cascade resolves before the Shapeshifter itself enters, so a permanent you cascade into and cast this turn becomes a legal thing to copy, letting the free spell set up the body it turns into. The name gestures at Sakashima the Impostor, the legendary shapeshifter whose whole identity is being someone else, and this reads as the apprentice's version of that trick: less the flawless mimic, more the opportunist who shows up at instant speed and free-rolls a spell on the way in.