Legion of Super-Heroes #110 (1989 4th Series)
The Power of Thunder!" You saw her on the poster in Legionnaires (1993) #50, you met her in the "Dead Earth" Annuals, and now the Legion meets the future inheritor of the power of Shazam: the heroine known as Thunder! When Dr. Savant -- mad leader of a magic-hating 30th century suicide cult on the planet Fawcettworld -- blows up the Rock of Eternity, the heroine from an even more distant future than the Legion is stranded in the 30th century! Will Thunder's efforts to gather the pieces of the Rock in an attempt to get home succeed?