Superman Vol. 2 #93A

In Superman Vol. 2 #93 (DC Comics, September 1994), Superman and Supergirl battle 68th-century aliens in Metropolis as a hologram warns of a time-eating crisis. Prioritizing family, Superman visits the Kents in Smallville, encountering Jor-El and Lara, who claim Krypton survived and offer to take him home. Doubting them as anomalies, he witnesses their serum fail and their ship destroyed by lightning. Metron confirms they're from an alternate timeline. Superman reaffirms his love for the Kents before departing with Metron as Zero Hour approaches.