If a cockroach comes in I'd suggest switching to one of the Shale Hatchlings. Since he casts Apocalypse followed by Shell Shield, you have a round to get your hatchling in, a round to get Stoneskin up, and then just Poison Spit from that point on.
The strategy offers a TD script that can be used with the TD Script addon. You can copy the script by clicking on the button to the left of the pets.
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