Board Thread:Plants vs. Zombies 2: It's About Time/@comment-25702176-20150302050314/@comment-24765950-20150302155817

Yeah, I've seen that before.

It's because there's a frozen imp just near the front of the lawn, but not fully on the board. You'd need to use Plant Food, a Cherry Bomb, or another AOE instant plant to take it out, as most plants won't attack things that aren't on the lawn.

Hope this helped.