Another word for monstrous

Monstrous gray rocks jutted up from the earth and found themselves entwined with honeysuckle and briar vines.
Despite his monstrous habits of shredding anything in his path, he had a sense of honor more deeply ingrained than she'd ever suspected.
And if there were more of those monstrous spiders on board, she probably did not want to wander around opening doors at random.
Lori always did have a way with Josh, even back when they were kids and she had a monstrous crush on him.
After a series of phone calls to Denver and some monstrous lies, Dean managed to finagle a slot on the bike tour, not an easy accomplishment given the short time before the popular event.

What's another word for monstrous?