Karai's Technique (Teenage Mutant Ninja Turtles #152)

Sorcery - {1}{W}{B}
Sneak {W}{B} (You may cast this spell for {W}{B} if you also return an unblocked attacker you control to hand during the declare blockers step.)
Choose one or both —
• Target creature gets +3/+3 until end of turn.
• Target creature gets -3/-3 until end of turn.