From the Dr. Seuss Classic Book Characters Party Supply Collection. Dr Seuss Classic Book Characters Invitations. Invite all your friends with these Cat In The Hat, Grinch, Horton and Green Eggs and Ham themed invitations that feature the classic characters from the books you love by Dr. Seuss. Includes 8 invitations and 8 envelopes. This product is officially licensed by Dr. Seuss Properties™ ©Dr. Seuss Enterprises, L.P. All Rights Reserved.