Put a small blob of yellow paint on the top third of the canvas, then a orange blob on the middle third, then a orange blob on the bottom third.
Carefully brush the bottom two thirds of the canvas with the orange paint, making sure you paint the sides as well.
Then carefully blend the orange into the yellow paint to have the color blend. Let the paint dry.
Paint your kids feet green one at a time and press them into the center of the canvas. Let the paint dry. Paint the toes black.
Glue the eyes onto the face. Paint on the smile, stitches, and the nuts with the black.
Dip your brush into the black and the yellow, write out trick or treat, smell my feet. Let it dry.