Splintering Wind
A repeatable Pestilence dressed up as a token engine, and the strangeness is entirely in the bookkeeping. Spend three mana and you get a point of damage plus a 1/1 flyer; spend it again and you get another, and another, until your board is a cloud of fragile splinters each demanding green mana every upkeep to survive. The throttle is built into the tokens themselves: each Splinter accrues age counters, so one you kept around for three turns costs three green to maintain, and the moment you cannot (or choose not to) pay, it dies and pings you and every creature you control for one. That last clause is the real design comment. The tokens are not just bodies, they are a self-inflicted Pyroclasm waiting to go off the moment your mana runs short, which means the card punishes the same overextension it tempts you into. Alliances was full of these high-friction green enchantments that asked you to keep feeding mana into an engine, and this is among the most demanding: the front-end rate is generous and the back-end ruinous, with the age-counter clock keeping the flying army from snowballing past what a single green deck can actually sustain. It reads like value and plays like a slow-motion liability.
Rules text
: This enchantment deals 1 damage to target creature. Create a 1/1 green Splinter creature token. It has flying and "Cumulative upkeep ." When it leaves the battlefield, it deals 1 damage to you and each creature you control. (At the beginning of its controller's upkeep, that player puts an age counter on it, then sacrifices it unless they pay its upkeep cost for each age counter on it.)