Mirri blocks the Locust Swarm.
Swat the Swarm. Resolves. Giant Growth fizzles.
Assuming no further responses from you, Mirri does nothing to the non-creature it had been blocking, receiving no counter.
You take 5 damage from the unblocked Spined Wurm, which triggers my Thunderblade Charge.
I'll tap out to deal 3 damage to Mirri.
Done.
Mooseman: 14
Hand: 1
Library: 19
Battlefield:
(TTUU) Swamp x4
(TUU) Forest x3
Gravity Well (E, Whenever a creature with flying attacks, it loses flying until end of turn.)
(S) Mirri the Cursed (3/2, Flying, first strike, haste Whenever Mirri the Cursed deals combat damage to a creature, put a +1/+1 counter on Mirri the Cursed.) ** DEAD? **
Graveyard: Nirkana Cutthroat, Slithery Stalker, Unhinge, Titanic Bulvox, Durkwood Boars, Child of Night,Vampiric Link, Mortal Wound, Swat
Exile:
--------------------------------------------------------------------------------------------
rokapoke: 16
Hand: 1
Library: 22
Battlefield:
(TT) Forest x2
(TTTT) Mountain x4
(T) Spined Wurm (5/4; Wurm; 0: Taunts you for a second time.)
Graveyard: Wayfarer's Bauble, Nessian Courser, Thunderblade Charge, King Cheetah, Hulking Ogre, Mudbrawler Raiders, Armor of Thorns, Giant Growth, Locust Swarm
Exile: