God-cursed brutes

Baboon,
originally uploaded by milkfish.

The illustration of the musculature of a snarl is from a book of gross anatomy of primates (baboons, chmpanzees, and humans) and makes me think about the Beowulf story and the first of the monsters in it, Grendel. From Seamus Heaney's translation:

Suddenly then
the God-cursed brute was creating havoc:
greedy and grim, he grabbed thirty men
from their resting places and rushed to his lair,
flushed up and inflamed from the raid,
blundering back with the butchered corpses.
Lines 120---125

Maybe Grendel could have been an enormous baboon larger than a man, his fangs and claws used to grab and carry off his prey, for some reason impervious to edged weapons but susceptible to Beowulf's might in their one and only fight, at the climax of which he has his arm and hand torn off. I could imagine that. Then Grendel's mother would be an even larger sort of baboon wreaking vengeance on the Danes on account of her loss then retreating to her marshy lair, where she too is confronted by the hero:

Quickly the one who haunted those waters,
who had scavenged and gone her gluttonous rounds
for a hundred seasons, sensed a human
observing her outlandish lair from above.
So she lunged and clutched and managed to catch im
in her brutal grip; but his body, for all that,
remained unscathed: the mesh of the chain-mail
save him on the outside. Her savage talons
failed to rip the web of his warshirt
Lines 1497--1505

So perhaps an amphibious, part-human, part-baboon enormous monster race of super-mandrills or the like, able to wield a knife (line 1546) and adapted to live in frigid northern waters. I think that would make a pretty good spectacle, in a graphic novel format or in CGI video.