Take your hoodie! and ur Felt, you need 3 different colors including white and black but MORE white.

measure the inside but front of the hood with a measuring tape. (where the green line is)
once you have that number just get that much of your white felt and draw mountains on it, like this
-----> ^^^^^^^^^^^^^^^^^
these are going to turn out as your teeth.

Then choose where you want your eyes to be, how far apart or whatever, nut make sure they are on the top where your head would fit.
their are many types of eyes to do so don't be afraid to experiment. =D

take your row of teeth and cut it out, u can either stick the whole row in or individually place each one, sticking everything together is your choice really, you can use a strong glue, a simple needle, or any other way you can think of.
then your DONE! =D YAYYY!!!! =p