Hasbro Pulse has confirmed, as we expected, that the Red Skull pack leaked a few days ago is an SDCC exclusive for 2018. The set includes a 6" scale Red Skull with Tesseract accessory. You also then get an electronic 1:1 scale Tesseract. The whole set is presented in a special presentation box.
Price at the show is $59.99 and we'd expect there to be some residual stocks on Hasbro Toy Store for US customers after San Diego.