Board Thread:Plants vs. Zombies 2/@comment-31058241-20171022172048/@comment-26127523-20171023060956

IIRC: -Explode-o-Nut

-Citron with PF -Grapeshot, but you need to position it right on the Gar. as the bouncing grapes that all (or mostly hit) will finish it off

This seems to confirm this list... http://plantsvszombies.wikia.com/wiki/Grapeshot "Notably, a Grapeshot under the right circumstance can instantly vanquish a full health Gargantuar (besides a Jurassic Gargantuar), a feat that can otherwise only be achieved by Electric Blueberry and Citron's Plant Food effect."