Elves you control have "Whenever this creature becomes tapped during your turn, untap it and put a +1/+1 counter on it. This ability triggers only once each turn."
Flood the board with cheap Elves, then use Dionus to turn every tap effect into permanent +1/+1 counters while generating absurd mana. You ramp explosively with Elvish mana dwarves, deploy a wide Elf army, and either swing with a huge counter-pumped board or funnel mana into a game-ending payoff.
Explosive mono-green ramp via Elf mana producers
Repeatable untap means double mana and counters from tap-based Elves each turn
Goes very wide and very tall simultaneously with counters
Cheap commander that rebuilds boards quickly
Extremely vulnerable to board wipes given the go-wide plan
No built-in card advantage or interaction in the command zone
Dies to targeted removal slowing the engine
Mono-green struggles to deal with fliers, enchantments, and protected combo decks
Legendary Creature — Elf Druid
