McDonald's Happy Meal web site confirms that the October 2015 kids' meal theme will be based on the current film Hotel Transylvania 2 (not The Nightmare Before Christmas, which was released back in in 1993).
There are differences in the shell textures of oysters and clams. The shell of a clam is smooth and shiny while an oyster has a rough outer shell. Both the organisms take in water through the shells but the filtering procedure is different. Oysters produce pearls which are in much demand but clams do not.
1 To take oysters or clams for recreational purposes while aboard a vessel where any person is engaged in commercial oystering or clamming.  To recreationally harvest oysters or clams within a leased area, harvest reserve area, sanctuary or any other area closed by the State.