User blog comment:A Graalian/Who would you rate the hardest Zombie in PvZ2 and OP plant in PvZ2?/@comment-24828059-20150412150206

Zombie: Wizard (Big surprise, right?). Although not a big deal in regular levels, they are probably the worst zombies in Arthur's Challenge and Pinata Parties. They stay in the back, as they move very slowly, while stronger zombies such as Knights are taking damage. Not to mention their ability to attack while off-screen.

Plant: Dunno, maybe Sun-shroom in PvZ2. For his cost, he managed to produce quite a lot of sun. In Endless Zones, I still find Twin Sunflowers better, but Sun-shroom definitely beats them in the regular levels.