Boil eggs and cut in halves. Remove the yolks in a separate bowl. Add tuna and mayonnaise.
Put the mixture back into the egg halves. Each olive cut in half. Place the halves of olives in the center of each egg. Cut the remaining olives in half, and after that cut the olives into small slices. These segments will be the spider legs. Put "feet" around each half of the olives on the egg, remember that a spider has usual eight - 4 on each side. Enjoy your Halloween's party!!!