Make shark decoration 1 day in advance.
Add 1/4 teaspoon Gum-Tex to 7 oz. white fondant. Tint 3 1/2 oz. white fondant each gray and black (use a little black color to make gray). Use fondant roller with purple guide rings to roll out black and gray fondant, separately, 1/8 in. thick. Use head pattern, knife and black fondant to cut out backing for entire head. Use knife to trim 1/8 in. smaller than pattern on all sides. Use head pattern, knife and gray fondant to cut out full-size head, cutting out mouth area. Use damp brush to attach gray head to black backing. Use lower jaw top layer pattern, knife and gray fondant to cut out lower jaw. Use damp brush to attach jaw to head.
For teeth, roll out white fondant 1/8 in. thick. Use pattern, knife and white fondant to cut teeth. Use damp brush to attach teeth to mouth. For eyes, use black fondant to roll ovals, 1/8 in. x 1/4 in.. For nostrils, use black fondant to roll balls, 1/8 in. dia. Flatten balls. Use brush with water to attach eyes and nostrils to head. Place shark on cornstarch-dusted cake board. Let dry 24 hours.