Vigor + Hanabi Blast + Crystalline Crawler + Conspiracy Theorist + Obosh, the Preypiercer

Vigor

Hanabi Blast

Crystalline Crawler

Conspiracy Theorist

Obosh, the Preypiercer

How it works

1. Cast Hanabi Blast by paying 1, targeting Crystalline Crawler.
2. Resolve Hanabi Blast, putting four +1/+1 counters on Crystalline Crawler due to Vigor's first ability, and then returning Hanabi Blast to your hand and discarding a card at random.
3. Conspiracy Theorist's second ability triggers, allowing you to exile the discarded card from your graveyard if it was a nonland card and cast it from exile this turn.
4. Activate Crystalline Crawler's first ability three times by removing three +1/+1 counters from it, adding 1.
5. Cast Hanabi Blast either from your hand or from exile by paying 1.
6. Repeat from step 2.
7. Once you have infinite colored mana, you may instead target any other creature and/or player with Hanabi Blast.

This brilliant loop relies on Vigor's replacement effect to turn the damage dealt to your own creatures into massive growth, allowing Crystalline Crawler to absorb the blow and stack up counters that can immediately be stripped for mana. When you fire off Hanabi Blast, its damage is doubled by Obosh, the Preypiercer's static ability—provided Obosh is your companion—turning that initial spark into a towering four damage that Vigor translates into four +1/+1 counters on the Crawler. As Hanabi Blast bounces back to your hand and forces a random discard, Conspiracy Theorist steps in to let you pluck that discarded nonland card right back out of the graveyard to recast it. By shaving three of those newly minted counters off Crystalline Crawler for mana, you have all the fuel you need to keep casting Hanabi Blast over and over again, eventually dealing lethal damage to any target once your mana is infinite.