Name This Marvel Villain??
Judging by our villain's murderous disposition and his preferred method of attacking his victims, whoever is on his hit list would be well advised to watch their back--as well as their front, their sides, and any other direction this foe might pounce from.
In this case, his target is construction worker Sigurd Jarlson, who you might recognize as Thor, the God of Thunder. Exactly why this villain is after Thor remains as much of a mystery as his identity--but the latter, at least, is something that's cleared up when he announces his intentions to his chosen prey.
As carnivorous and predatory as his namesake, the Mongoose is unfortunately more sadistic and vicious in humanoid form, surprising Jarlson with his speed, strength, and his tendency to rake his victim with his claws (and, given the opportunity, his very sharp teeth). Thanks to the timely intervention of Spider-Man, Jarlson's life is saved after he's hurled to his presumed death--and once safely on the ground, he takes measures to better confront his foe as his more famous alter-ego.
Somebody does get clobbered, and it's the Mongoose--though "driven off" is a more accurate way of putting it, since he puts up a very good fight against both Thor and Spidey but decides to retreat while he can.
The question remains, however, just why he was after Thor. The short answer would be that he wanted to kill him, of course; but the Mongoose is actually assigned to obtain something from the Thunder God, a mission which becomes more clear when he conscripts the deadly Quicksand to help deal with Thor.
We can cut to the chase a bit here and divulge that the Mongoose is one of the High Evolutionary's "New Men," as is his supervisor--and their reason for wanting cell samples from Thor is to expand the Evolutionary's experiments to the creation of new gods. The problem is that the Mongoose has turned out to be too uncontrollable, too vicious and murderous to trust--and eventually, in the area of the Balkan mountains known as Wundagore, he's rejected by his fellow New Men and subsequently seeks vengeance on Thor, who has arrived with his friend Eric Masterson. Now armed with the advanced weaponry of Wundagore, the Mongoose has Thor on the ropes--forcing Eric to step in and prove his worth and friendship to Thor, in a most startling way.
The Mongoose is driven off by the arrival of Hercules--but the damage has been done. Eric is near death--and Thor calls out to his father, Odin, to save him, bringing us to the point in the book where Eric is given new life by restoring Thor to a dual identity that goes much further than a simple change of clothes.
By accounts, the Mongoose goes on to join the Thunderbolts in order to avoid jail, and eventually becomes part of the fifty-state initiative designed to place a super-team in each state of the country. Now that's a teammate you want watching your back, eh?