ThunderCats - Season 2 Episode 8

Mumm-Ra plans on using the legendary Mask of Gargon to free a sleeping child in the hills of Elfshima to use against the Thundercats. When Chilla and Tug Mug fail to get the mask because it turned them to stone, Mumm-Ra summons it and decides he needs the Eye of Thundera so that the mask can use sight beyond sight to awaken the giant child. Lynx-O warns the Thundercats of the mask and the sleeping child, but Lion-O, Panthro, and Willa still go to the pyramid, but are turned to stone by the mask. Mumm-Ra then uses the Eye of Thundera and the mask to awaken the giant. But Lynx-O and Ben-Gali in the Thunderstrike defeat the giant and the mask gets smashed apart restoring everyone who had been turned to stone, and the Eye of Thundera burns the book that contained the mask's terrible secrets.