If you give students half of a symmetrical image, they will have all the info they need to complete the missing side.
If you search for spiders at “Clip Art ETC” you will find THIS amazing collection. You may have trouble deciding which one to download. I chose the highest resolution of a fuzzy one, and cropped it in my computer to print just half an image. For those in a hurry, HERE is where you can drag a copy to your desktop. I recommend that students start with drawing the outside edges until they think the shapes match, and then fill the inside to match. Lots of shading will be necessary to complete the spider.