Follow the ouroboros down valleys and over mountains. Is it even going anywhere?
EDIT (7 days after initial posting): The grid and Penpa+ link have been updated to an easier version, with more numbers filled into the grid. The solution remains unchanged.
Did the ouroboros...
...join a CULT?
First, we solve the slitherlink:
Next, the lines are reminiscent of
an origami fold diagram. Specifically, the dashed lines are called "valley" folds, and the dot-dash lines are called "mountain" folds.
The "ouroboros" seems to refer to
the slitherlink loop itself, so the edges are what's important - ignore the cell coloring (this tripped me up for a while).
So to get the final solution, we can
print the solved slitherlink and fold along the lines:
