Board Thread:Plants vs. Zombies 2: It's About Time/@comment-25226017-20140725232047/@comment-4009269-20141202192157

That's probably why they removed it. It was one update after Gargantuars were added, and maybe they figured they could get more money if they replaced a cheap powerup that could insta-kill Gargs with an expensive powerup that takes half of its duration to kill a Garg.