Avalanche Riders

Stone Rain on legs, and the echo cost is the entire reason the body is allowed to come stapled with the spell. Land destruction had always been a sorcery you cast once; here the destruction rides in on a hasty 2/2 that can attack the same turn it resolves, which would be a flatly better Stone Rain if it ended there. It does not end there. The echo trigger forces the choice on your next upkeep: pay again to keep the creature, or let the upkeep trigger sacrifice it, having already pocketed the destruction. That structure reframes the whole card as a flexible one-shot. Against a deck you want to keep beating down, you re-buy the body; against a deck where the land was the only thing you cared about, you let it die and never pay another cent, the enters trigger having fired the moment the creature resolved regardless of whether you ever pay echo. The interaction the design quietly assumes is reanimation or flicker: any effect that returns or blinks the Riders re-fires the land destruction and imposes a fresh echo cost, turning a one-time Strip Mine on a stick into a recurring assault on a mana base. The haste-plus-echo skeleton is doing the work that flashback's exile clause does elsewhere: it bounds the rate by making the body temporary unless you keep paying to hold it.