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.
Oskar triggers if the discarded card was a nonland card.
Holding priority, activate Crystalline Crawler;s first ability three times by removing three +1/+1 counters from it, adding ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Resolve the Oskar trigger, choosing to cast Hanabi Blast if it was the discarded card by paying ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) targeting Crystalline Crawler, or choosing not to cast the card otherwise.
If you did not cast Hanabi Blast using Oskar, cast it from your hand by paying ({1} magic symbol) ({R} magic symbol) ({R} magic symbol) , targeting Crystalline Crawler.
Repeat from step 2.
Once you have infinite colored mana, you may instead target any other creature and/or player with Hanabi Blast.