If you plan to make a gorilla costume, there are some things you must do before you begin the project. First, take base measurements of the person for whom you are making the gorilla costume. Add at least 6 inches to every limb measurement and as much as a foot to the torso, to allow for padding. You will not need to sew the mask portion, but you should get the circumference of the head. Next, make sure your sewing machine is equipped with a heavy-duty needle and that you have at least one back-up needle, in the event of a breakage. Find and print close-up images of a gorilla face and torso, for reference.
To make your gorilla costume, you are going to need white cloth marking chalk, good sewing scissors, 100 sewing pins, several spools of black thread, a black or dark grey ski mask, socks and gloves, a dozen 8x10 sheets of black craft foam (or any color foam and black acrylic paint), strong craft glue, a roll of quilting material, 2 yards of elastic ribbon, several large sheets of butcher paper (or newsprint), and as many yards of black or dark grey fabric and black faux fur as indicated by your earlier measurements.
Using your measurements (plus 7" for padding and seam allowance), draw and cut out basic patterns out of the butcher paper, one for a standard long-sleeved shirt and the other for standard pants with no fly. Pin the pattern to a double thickness of the fabric and either trace the outline with the chalk, or cut the fabric around the pattern itself, so that you have 2 pieces for the "shirt" and 2 for the "pant". Cut the quilting material to fit each portion of the outfit (i.e. sleeve, chest, etc), and sew it onto the back side of the fabric. Repeat this process with the fur, sewing it onto the opposite side of the fabric, but do not sew any onto the chest portion of the gorilla costume.
Next, place the back and front portions of the costume top together (with quilting sides out) and sew in place, leaving gaps for the waist, wrists and neckline. Repeat with the pants, leaving the cuffs and waist open. Sew elastic into the waistband of the pants. Using the photos for reference, use foam to create the chest of the gorilla costume, and also the gorilla's face, affixing the foam onto the chest and ski mask with the craft glue. Use the black paint, if necessary. Cut pieces of the fur and glue these onto the top sides of ski mask, gloves and socks. Pad the bottoms of the socks by gluing a couple of thicknesses of the craft foam on the outside, for comfort.