This is a video of a species of predatory nudibranch sea slug (Melibe leonina) repeatedly showing off its giant mouth in the search for food. It kind of reminded me of someone trying to stretch their scrotum over the bright end of a flashlight. "Um, what?" I was a biology major in college. "You said you were a marketing major." I was, my biology major was entirely extracurricular. "I don't even want to know." You absolutely don't, believe me.
Keep going for the whole video.
Thanks to pintail, who agrees Mother Nature should really stop inventing animals when she's hopped up on cough syrup and model airplane glue.