Step 10: Below the horizontal guide, draw a big shape similar to the letter D on its side for Beast Boy's mouth. The top of the mouth should be very close to the bottoms of the eyes. Make the shape wide too.
Step 11: Inside the mouth, at the top, draw an angled line for the top row of teeth. Make the left side of the line pointy for the canine. At the bottom of the mouth, draw a curved line for the tongue. On the bottom, left side, draw a small, triangular shape for the bottom canine.
Step 12: Use the C-shaped line on the left side of the head as a guide to draw Beast Boy's first ear. Darken the bottom of the guide. At the top, make the lines longer for the pointy ear. Curve the lines farther inside the ear. Add an angled line within the ear for structure. Use the line on the right side of the ear as a guide to draw the other ear the same way. Make the tip pointy and the overall shape smaller because of the way this Teen Titans Go! character's head is turned.
Step 13: Use the bottom edge of the initial square as a guide to draw the lower half of the head. Follow the basic path of the guide and darken the lines to create the jaw and chin. Curve the corners as you darken the line so that the sides of the head aren't too sharp. On the right side of the ear on the left, draw a curved, vertical line for the first part of the front of the hair. Near the top edge of the head, draw a long, curved, horizontal line across the head for Beast Boy's hairline. The line should angle in the middle for a clump of hair. On the right, the line should extend outside of the head.
Step 14: Use the top of the initial square as a guide to draw the rest of Beast Boy's hair. On the top, left corner of the guide, draw three spike-like, triangular shapes for the hair standing up. Don't make these shapes too big. The middle spike should be the biggest. Draw a long, curved line above the edge of the initial square for the top of the hair. The line for the top part of the hair should curve up and then back down on the right side like a wave. On the right side, draw three short, spike-like shapes for the pointy tips of the hair.