Famed alchemist Nicolas Flamel (Brontis Jodorowsky) pops up in The Crimes of Grindelwald in a few delightful scenes, one of which includes a glimpse of the glowing red sorcerer's stone that he has hidden in a cupboard in his apartment. It's presumably how he was able to achieve immortality, since drinking the stone's legendary Elixir of Life is rumoured to keep a human being alive forever.