Wild-Magic Sorcerer

Cascade was designed as a one-shot cost-reduction lottery, a trigger you got when the spell entered the stack: cast Bloodbraid Elf, resolve one free hit, move on. This bottles that trigger and reattaches it to a condition you control instead of a spell you cast, granting cascade to the first spell you play from exile each turn. That relocation is the whole design. Cascade normally lives on a specific card, so you get exactly as many free flips as you have cascade cards; here the flip is a property of a zone-crossing, and any spell can carry it if you route it through exile before casting. The rate lives on that word "exile," which is doing quiet work. Foretell, adventure, plot, suspend, and impulse-draw effects that stash cards face-up all feed the same engine, provided the payoff is a spell you actually cast from exile rather than something dumped onto the battlefield. Each turn refreshes the counter, so a steady drip of exile-casting becomes a steady drip of free spells. The 4/3 body is the price: undersized for four mana, it wants you spending the game casting from exile rather than defending it. What makes it worth building around is the reframing: it turns a keyword everyone treats as a static bonus welded to one card into a repeatable engine, and the cards that fill exile were never designed with cascade in mind, which is precisely why the interaction feels like it is getting away with something.