Sphinx of Forgotten Lore

Flashback normally lives in the graveyard as a printed clause: cast it once from hand, then it offers you a second use at a fixed price before exiling itself. Here, the flashback is granted from the battlefield instead, and it is granted on attack, which turns a defensive-looking flash flyer into a recurring spell engine tied to combat. The trigger hands one instant or sorcery in your graveyard flashback for its own mana cost, so the reward scales with what you have already spent: a cheap cantrip comes back nearly free, while a bomb sorcery still costs its full freight. The flash keyword is what stitches the two halves together. You can hold it up as an instant-speed interaction (bounce, counter, whatever else sits in blue's toolbox), then deploy it end of turn and untap into an attack that lets you recast a spell already in the yard for its mana cost. It also means the body can ambush on defense and still convert to offense the following turn. The 3/3 flying frame is modest by design; the card is not asking to win combat so much as to keep buying back the spells that already earned their keep. Because the flashback duration lasts only until end of turn, each attack forces a choice about which single card in the graveyard is worth casting right now, rather than opening the whole pile at once.