The Battlefield

Gravecrawler
Grimgrin, Corpse-Born
Rooftop Storm
AI DraftFeb 26, 2026

Gravecrawler + Grimgrin, Corpse-Born + Rooftop Storm

Overview
With Grimgrin, Rooftop Storm, and Gravecrawler under your control you may cast Gravecrawler from your graveyard (Gravecrawler's own permission) and Rooftop Storm makes its mana cost {0} so you can cast it for free; after it resolves you may sacrifice that Gravecrawler to Grimgrin's sacrifice ability to untap Grimgrin and put a +1/+1 counter on it, then cast Gravecrawler from the graveyard again — repeating this loop produces arbitrarily many +1/+1 counters as long as you can cast Gravecrawler from the graveyard each time (you must control a Zombie when you begin casting) [2011-01-22] [2011-09-22].
Step 1
Ensure the board state: Grimgrin and Rooftop Storm are on the battlefield under your control, and at least one Gravecrawler card is in your graveyard; Grimgrin is a Zombie so it satisfies Gravecrawler's "you may cast this card from your graveyard as long as you control a Zombie" condition .
Step 2
Start the loop by casting Gravecrawler from your graveyard. Rooftop Storm lets you pay {0} instead of Gravecrawler's mana cost, so you may choose that alternative cost when casting; casting places the spell on the stack and follows normal timing/priority rules .
Step 3
Once Gravecrawler is on the stack, if you somehow lose control of the Zombie that allowed you to begin casting, the cast still continues and the spell will resolve normally — the requirement was checked as you began casting [2011-01-22].
Step 4
Allow the Gravecrawler spell to resolve; it enters the battlefield. (If it is sacrificed or otherwise moved before resolving, normal rules about spells on the stack and moving cards apply .)
Step 5
Activate Grimgrin's ability: "Sacrifice another creature: Untap Grimgrin and put a +1/+1 counter on it." Sacrifice the Gravecrawler you just cast. That sacrifice puts Gravecrawler into your graveyard , the activated ability goes on the stack, and when it resolves Grimgrin is untapped and gets a +1/+1 counter.
Step 6
With Gravecrawler back in your graveyard and Grimgrin still a Zombie you control, you may repeat: cast Gravecrawler from your graveyard for {0} (Rooftop Storm) and sacrifice it again to Grimgrin, accumulating more +1/+1 counters. Repeat as long as you have priority and the necessary game resources.
Step 7
Note that Rooftop Storm replaces only the mana cost; any mandatory additional costs would still need to be paid when casting [2011-09-22].
Resolution
If you control Grimgrin and Rooftop Storm, you can repeatedly: cast Gravecrawler from your graveyard for {0} (Rooftop Storm), let it enter the battlefield, sacrifice it to Grimgrin's "Sacrifice another creature" ability to untap Grimgrin and put a +1/+1 on it, then cast Gravecrawler again from the graveyard — producing as many +1/+1 counters as you like so long as the casting-condition (controlling a Zombie at the time you begin casting) is satisfied each time. Once a Gravecrawler spell is on the stack, losing control of that Zombie doesn't undo that cast [2011-01-22]; Rooftop Storm only replaces the mana cost, so any mandatory additional costs would still need to be paid [2011-09-22] .
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