Blue sea slugs (Glaucus atlanticus)  feed on the venemous Portuguese man o' war. as they are immune to their venom.

Look closely, what do you see? With the incredible ability to camouflage itself against a tree limb, a wrap-around spider can make itself nearly imperceptible. Dolophones conifera are native to Austrailia. 

The larvae of the Pink Underwing Moth has an extraordinary defense mechanism. When threatened, it curls it's body to reveal a fierce "face".