DIY Knit Shark Hat Free Pattern by Allison MacAlister of knittingninja.com here. Photos from pattern and people on Ravelry who have knitted this popular hat here.
DIY Knit Shark iPhone Cover Free Pattern by Reuben Briskie on Ravelry here. As I always mention, Ravelry is a sign up site (no spam) with lots of free and pay knitting and crochet patterns. First seen on Make here.