Start by cutting a half-apple shape out of red Foamies craft foam (you can use a real apple for visual reference). Next, cut the same shape out of white craft foam, but trim the outer edge about 1/4 to 3/8 inch all around so that it is slightly smaller than the red cutout. Use tacky glue to glue the white cutout on top of the red one. Then, cut out a black foam stem and glue it in place. With a fine-tipped permanent black marker, sketch a thin vertical line in the center of the apple (the white side) and draw on a couple of apple seeds.

Now, loop a piece of braided black yarn onto a key ring so that there are two lengths extending from the ring. Using a wide-eyed needle, thread one end of the yarn through the apple at the base of the stem, then tie an overhand knot in the yarn to keep it from slipping back through. String beads onto the other length of yarn, knot the end and you're ready to attach a key.