It's sort of a beginner-plus pattern, maybe early intermediate. All you really need to know how to do is knit, purl, and basic cable. Helps to be handy with a set of double-points or circulars too, but that's all hats. I had a pattern for horns, but got bored and decided it really didn't need it. I call my finished confection the Saxon. My boyfriend (the recipient of said confection) prefers to refer to it as the Gimli. Whatever. It'll make a nice balaclava when the weather gets cold (and in St. Louis, however remote that seems in late August, it will get cold). The helmet itself is a variation on the basic beanie. You pick up stitches for the noseguard. The hair's stockinette with a basic 3-part cable thrown in. May there not be a lack of cool headgear for future generations!
Hat (approx. adult medium):
Cast on 90 stitches (or some multiple of 3) smooth worsted-weight yarn, join and work in round.
Rows 1+2: purl all the way around.
Rows 3+4: knit.
Row 5: *k5, bobble, repeat from *
bobble: k front and back in same stitch (makes 4 total), turn, purl those 4 stitches, turn, slip 1st stitch, k2tog, pass slipped stitch over, knit, pass slipped stitch over.
Rows 6+7: knit.
Rows 8+9: purl.
Row 10: *k13, p2, repeat from * to end (should make 6 evenly spaced narrow bands).
Continue approx 3-3/4 inches then begin decrease (remembering to maintain the 6 sets of p2's throughout for the "metal" bands):
Decr 1: *k4, k2tog, k4, repeat from *
Row 2: knit (knit all even rows)
Row 3: *k7, k2tog, repeat from *
Row 5: *k3, k2tog, k3, repeat from *
Row 7: *k5, k2tog, repeat from *
Row 9: *k2, k2tog, k2, repeat from *
Row 11: *k3, k2tog, repeat from *
Row 13: *k1, k2tog, k1, repeat from *
Row 15: *k1, k2tog, repeat from *
Knit 1 additional round, break thread and pull through.
Noseguard: pick up 8 stitches from front and center of hat, knit across. Continue approximately 8-10 rows until about mid-nose, then decrease. For decreases, k2tog, knit to last 2 stitches, k2tog all odd rows, knit all even rows. At last 2 stitches, k2tog and bind off.
Hair/beard: Pick up 54 stitches from back/sides of helmet, knit across using appropriate yarn (I used Lionbrand Homespun, an old frenemy).
Knit across for 3-4 rows, ending on a wrong side row.
Cable as desired for braids. In my case I did a 3-part cable very much like an actual braid (sl 4 sts, bring to back, k4, knit slipped sts, followed 4 rows later by k4, sl4 sts, bring to front, k4, knit slipped stitches), but I advise playing around with it a bit before settling with your pattern of choice.
At the end of the noseguard (approx 12 rows or so), cast on remaining 36 stitches, picking up 2 from noseguard in the center. Join and work in the round. Again, insert cables as desired for braiding in the beard. Knit to desired length and bind off. Weave in loose ends and enjoy!
OK, I know the hair/beard part's a little less regimented, but honestly it works better that way. No two Vikings should look the same, right? Of course I'm right. That's what I'll keep telling myself, at least. Ooh, and maybe you can ditch the hair altogether for some chain mail, since that's easy enough to fake with a metallic gray yarn and garter stitch.
And now I'm fresh out of ideas for cool hats. Maybe I should take requests. Although I'll almost certainly categorically refuse a fez. I draw the line at Stetsons.