Spidera had been most welcomed by Mumm-Ra when she had been hatched in the Kingdom of Webs. The devil priest had transformed into a "helpless" Diamondfly and lured Lion-O to Spidera's lair, then the remaining Thundercats, in another attempt to rid his "Dynasty of Darkness" of them. Spidera had been formidable, with a height of over 80 feet, strong webs, and eight deadly claws to combat the cats set upon her. She had been ultimately pushed back into a deep cave and sealed in by the combined efforts of the Thundercats.