The Release of Abby and Jay Leno occurred on Day 5 of the Pokémon Red playthrough. As the name implies, ABBBBBBK( and JLVWNNOOOO were accidentally released.
Background[]
The Hivemind knew that Red would eventually need a Pokémon that could learn Surf. However, there was a schism amongst the Hivemind. One faction's plan was to evolve the Eevee given to the player in Celadon City into a Vaporeon. The other faction argued that this path would be too treacherous, requiring the Hivemind to select a water stone from the item menu on Eevee. They instead wanted to abandon Eevee and catch the Lapras in Saffron City, which would be simpler. In the end, the Eevee camp succeeded. However, a Fire Stone was accidentally purchased and used, and Eevee evolved into a Flareon
Again in need of a Pokémon that could learn Surf, the Hivemind went to the PC when they got to Saffron to free up space in the party for the Lapras.