Hi!
I don't knit much, I'm a crocheter, but I thought this would look better knitted. The eyes and teeth are crocheted. The set is inspired by ladylinoleum's crocheted eyeballs.
It looks a bit weird on DD, who is modelling, because it's made for her older cousin.
Hope you like it.

I can’t give you a real pattern, because I made it up as I went and don’t know the measurements. And English is not my first language. I don’t know, if this tute will be any helpful, but here you go:
Hat:
A simple tube knitted in rounds (1 knit, 1 purl) to fit head and a bit longer. Sew upper edges from the left like this (but evenly, of course, hehe):

Crochet eyeballs from this pattern:
http://www.monstercrochet.com/TomatoPattern.htmlI used variegated embroidery thread for the iris. Black and white cotton yarn in the same thickness.
On this website is a gollum hat with eyeballs. You could also use this pattern, it’s free, too.
You can use the lid pattern from the tomato, too or knit an halfcircle in stockinette stitch to fit on the eyeball.
Figure out, where to put the eyeballs. Best would be to do that on the recipients head. Pin in place ... carefully, hehe. Sew eyeballs to hat (I use invisible thread), leave an opening and stuff with polyester fill or snippets. Close opening. Sew lids in place.
Scarf:
Knitted in 1 knit, 1 purl, even count.

Start in red and increase slightly at the sides to make a nice tongue shape. Change to body colour in about 1/3 of desired length. After another 1/3 knit only half the way to make the opening for the mouth. After desired length, leave stitches on a stitch holder or simply start the second half with a new needle. When the second half is as long as the first knit over both halves to connect them. Knit to desired length. I can’t tell you, how to knit the points, but there was a lot to weave in :-D
Crocheted teeth:
Chain 4, sc in second ch from needle, dc in next ch, tr in next ch, that’s one tooth, repeat as often as needed. If you want pointier teeth: chain 4, sc in second ch from needle, half dc in next ch, dc in next ch, repeat.
If you are less lazy than I am, make four sets of teeth and sew them on both sides of the scarf and it will look the same, no matter what side is showing.