Decorate brownie. Prepare decorating bag with tip 7 and brown icing. Pipe around edges of ears. Using spatula and brown icing, ice top of reindeer smooth, leaving inner ear bare.
Prepare decorating bag with coupler and black icing. Using tip 8, outline nose and pipe eyes. Fill in nose and ice smooth with spatula. Change to tip 3; pipe curved line over nose.
Prepare decorating bag with tip 3 and white icing. Pipe highlights on nose and eyes.