To get started making the dinosaur teeth, cut out a 2 in. piece of white Duck Tape®. Then, fold both top corners down to the center to form a triangle with an exposed sticky strip along the bottom. Repeat as needed to cover the edge of your hood.
To attach the teeth, press the exposed sticky strip to the inside edge of the hood. Pro tip: Start in the center and continue down each side, so the teeth are evenly spaced.
For the dinosaur spikes, start by cutting a 5 in. piece of Duck Tape®. Peel all but the last 0.5 in. of the tape back from the cutting mat and loop the loose end of the tape back over itself without letting the sticky sides touch each other. Line up the edge of the tape so that it overlaps 0.5 in. from the original part that is still attached to the mat and press the tape together. This will form a double-sided flap with two 0.5 in. ends that are still sticky. Cut a triangle shape into the non-sticky tab, without cutting the sticky strips that are still attached to the cutting mat. You will then end up with a triangle shape with two rectangular sticky tabs on the bottom.
To complete your dinosaur costume, attach these triangular pieces all the way down the back of the sweatshirt, starting at the front center of the hood.