Having the qualities of a monster; deviating greatly from the natural form or character; abnormal; as, a monstrous birth.

Abounding in monsters.

abnormally large

distorted and unnatural in shape or size; abnormal and hideous; "tales of grotesque serpents eight fathoms long that churned the seas"; "twisted into monstrous shapes"

hideous and fearsome

an abnormal growth pattern. Growth originates from a many-centered point on the stem.