Into the Void

The price of doubling a bounce spell is paid in tempo: four mana to send two creatures home, where a one-mana Unsummon handles a single target sooner. That trade only justifies itself when the second body is doing real work, which is why a two-for-one bounce lives or dies on the board it answers. As a removal substitute it is famously soft, because nothing dies and the opponent recasts everything later; as a tempo swing it buys a full turn against a developed board. The sorcery speed is the real tax. A double-bounce that resolved at instant speed could clear two attackers off the board mid-combat, blanking an alpha strike after the opponent had already committed to it; confining it to your own main phase strips that ambush and reduces the card to a proactive tool you fire before combat ever starts. That timing limit is the line between a fair card and a format problem, and it keeps a two-target bounce honest in a way the cheaper single-target instants never needed to worry about. What it does best is peel two attackers off a developing race on your turn, or pick up a pair of your own creatures to re-trigger their enters-the-battlefield effects when you can afford to recast them. What it cannot do is generate card advantage: every creature it returns is a creature the owner gets to deploy again, summoning sickness and all.