Surreal Memoir

The randomness is doing two jobs here, and only one of them is obvious. The first is variance: you point this at your graveyard and take whatever it gives you, so the spell is only as good as the bin you've stocked. The second, quieter job is that rebound turns one random pull into two. Resolve it from hand once and the card itself waits in exile for your next upkeep, when you reach into the yard again and draw from whatever has accumulated in the interim. Each grab is independent, so the second pull can find a card the first one couldn't have. But "at random" is not the liability it reads as: with a single instant in the graveyard, the random clause becomes a guarantee, and players who want a specific target simply prune the yard until that target is the only legal one. The randomness only costs you when there are multiple instants you don't equally want back. Rebound also fixes the timing problem recursion sorceries usually carry: you pay four mana once and get the recur built in rather than paying again, so the value lands across two turns of one investment. It is Regrowth on instants with a delayed second cast, balanced by surrendering target choice. The design rewards either approach taken to its limit: a graveyard packed thin with instants you'd be happy to draw blind, or one sculpted down to the single card you're actually fishing for.