Ivy's Green Monster was a creature created by Poison Ivy in the video game Batman Vengeance.
The monster was created by Poison Ivy when she took over Gotham Chemicals with her plant creatures. Poison Ivy created the monster using her plants and her acid. She used the monster as her personal minion while the other creatures do her bidding.
After Batman defeated Trenchcoat , he confronted Poison Ivy who was blackmailing Mayor Hill for money. She sent the green monster to kill Batman. The Dark Knight knocked out two of the creature's tentacles with his batarangs and fired some of his batarangs at the pipes near it, causing the tentacles to shrink. Batman threw a batarang at the monster's last tentacle, causing it to fall into a vat of acid. Poison Ivy laughed if off, saying that the monster has a healing factor and Batman might have scratched the bark but can never reach the roots. Batman used his Bat-grapple to get across the vat to the other side of the room. He turned on the electric back up generating switch, turning the electricity back and electrocuting the monster still inside the vat, destroying it.