Detective Comics, Vol. 1 #823A

As Poison Ivy serves out her sentence in Arkham Asylum, a strange, and immensely powerful plant forces its way up through the floor of her cell and attacks her. She manages to escape both her attacker and Arkham, but turns to the Gotham Police and Batman for assistance. Batman gives her shelter in the Cave while he attempts to determine why a plant would be so intent on murdering Poison Ivy.