Fridge Logic - Anything to do with Mr. Freeze falls in this category.
Ahaha. Fridge Logic. I get it.
Icy what you did there.
That pun leaves me cold.
Poison Ivy was sitting in her chair/plant when she kisses Robin. She fights him and Batman. Then Batgirl comes in and they fight. Batgirl pushes her into the chair/plant which eats her... No reason was given as to why her chair just ate her...
One of two things happened: When simply lounging inside the plant, Poison Ivy didn't put enough pressure on its trigger mechanism to close it, but when she fell into it, the mechanism triggered and, like a perfect reflex action, the plant closed instinctively. Another possible reason is that Poison Ivy simply lost control of the plant due to being beaten up from the fight and her mind being otherwise occupied.
Fridge Horror: All this "Lighter and Softer Gotham" talk almost goes right out the window when we see that every nook, cranny, abandoned Turkish bath and street racing site is populated by gangs. Most of them look homeless, at least one is led by a sexual predator, and another is completely okay with raising a child around crooked, violent bike races.
Fridge Brilliance - Mr. Freeze is not having a moment of Bond Villain Stupidity at the beginning of the movie. His plan was to lure Batman (or even Robin) into a Friend or Idol Decision by freezing Robin and using that to cover his own retreat because his suit was running out of energy and his life would have been in danger if he had stuck around to fight Batman. In short, Mr. Freeze pulled a Batman Gambiton Batman!