If you were to personify the very first winter frost as it penetrates past your sweater and sends a chill straight into your bones, it would look a lot like a brinicle.
This underwater phenomenon is the result of cold, sinking brine (which is denser than water) sinking into a body of water, freezing everything it touches.
Last year, a group of videographers from BBC captured a brinicle forming while they were filming in Antarctica for the BBC One series Frozen Planet (talk about a fitting occasion). The turned a timelapse camera on the spectacle, and viola: the cold, chilling "finger of death" in real life.
Hugh Miller, one of the cameramen on the scene shared some words on the experience with BBC: "The one we'd seen a week before was getting longer in front of our eyes...the whole thing only took five, six hours."
Check out the video above, as the sinking brine forms an icy sheath around live sea creatures as it descends into the ocean floor.