Future Shock (Green Lantern 51)

Now that he's a homeless vagabond, Hal FINALLY follows up on the strange baubles he's found stuck to his uniform and *gasp* they're from 3800 years in the future! He travels to the 58th century only to find a clone of himself which HE CREATED. Confused? Join the club, sister! It's all right here in Green Lantern #51!