Separate dough into triangles. Press each triangle into serpent shape, with thin, tapered tail and wider head, on baking sheet. Head should be about 1/4 in. thick.Press Fruit Loops into head for eyes. Brush serpents with egg and sprinkle with seeds.Bake according to directions on pkg.When cooled, slice head end lengthwise to form a mouth. Mix tuna with mayonnaise to taste and fill mouth with tuna mixture. Add tomato strips for tongues.