Unnatural Speed

Granting haste for a single red mana is about as cheap as the effect comes, and on its own the trick is thin: it lets one creature attack or tap the turn it arrives, with none of the secondary upside (no card draw, no buff, no evasion) that later one-mana enablers learned to bundle in. The reason it exists is the Arcane subtype, which plugs it into the splice economy of its era. A splice card never resolves: it stays in hand, revealed and grafted onto a resolving Arcane spell for an additional cost, then returns to hand for reuse. Unnatural Speed is the opposite end of that transaction, the spell you actually cast and let go to the graveyard, carrying the spliced text along while the splice cards live to fire again. A one-mana Arcane instant is the cheapest possible trigger for a splice chain, a low-commitment way to open the sequence and fold in a haste rider plus whatever else you stack on top without overpaying for the privilege of starting. Cast for haste alone it is marginal; cast as the first note of a splice turn it is doing exactly the structural job it was printed to do.