Is the underwater creature in Lake Superior some kind of giant serpent or dinosaur throwback? Or is it just a giant fish?

Lake Superior's current monster resident has been named "Pressie" and is believed to be a monster serpent. Pressie got her name from sightings that occurred near the Presque Isle River. These sightings aren't all current: evidently, some centuries ago, early residents claimed to have witnessed this serpent-creature and dubbed it Mishipishu. The creature is said to have a serpent's body, a horse-type head, the tail of a whale, long neck, blackish-green and 75 feet long.

REPORTS MADE SINCE 1894 INCLUDE:
It's back sticks 6 to 8 feet above water
A 15 foot neck.
A foot-wide jaw.
It chases ships.
A man fell overboard and was grabbed & constricted, like a snake.
It can swim around 9 miles an hour.
Multiple humps.

 

As recently as the 1990’s, witnesses at Point Iroquois claim to have seen a buck deer being pulled into the water by some large underwater beast, which only left the buck's head on shore. 

SO, WHAT'S YOUR CONCLUSION?
A giant water snake?
Barracuda?
Fresh water octopus or squid (are there such things)?
Dinosaur throwback? 
Sturgeon?
Pike?
Giant eel?
The whole thing is bogus?

Let's face it, Lake Superior is MASSIVE and the existence of some unknown underwater creature is extremely possible. But until someone can take a decent, UNBLURRED picture or video of this creature, we'll have to just sit and speculate.

Watch & listen to the video below as one 1977 witness relates his sighting: