I have never seen Sharknado, nor do I feel the need to see it. However, I can admire the sheer brilliance of the idea. Instead of harping on one baseless fear (piranhas, lightning, vaccines, GMOs, fracking, etc.), the creators linked two together.
I have some ideas for the sequel:
An innocent spider is merged with an evil clown: Spider Clown is born!
Public Speaking with Snakes
I see Public Speaking with Snakes as more of a reality show. After all, who wouldn't want to see boring speakers eaten alive by a boa?
13 Rusty Nails
13 Rusty Nails could go two ways. Either the main character steps on a nail every time she sees the number 13, or she's pissed off some demonic carpenter and his magic nails chase her down one at a time.