We’ve already had multiple reports of this being false. So we dug in a bit and found some deep dives into this egg, and are sad to say that it is absolutely false. Sorry for the false alarm.
In the rumors category, but something worth trying. Another change the name game here. Rename your Charmander to Zippo and then evolve it.
When it evolves into Charmeleon it is supposed to have the moves Ember and Flamethrower
let us know your results, so we can move this from the rumors category to a verified Easter Egg! Also, if you can do more than one, let us know. This may be like the Eevee trick and only works once.
Zippo was introduced as a Charmander during the Indigo Plateau Conference, breaking open a wall in a van Team Rocket trapped Ritchie and Ash in with Slash when Ash’s Bulbasaur couldn’t do it on its own.