Pappy van Poodle, a character in Nintendo's Rusty's Real Deal Baseball, was so obscure no-one ever uttered its name on the Internet record despite his having an extensive in-game backstory and hand-painted media. That's zero Google or Twitter results—at least as of the publication date of Nick Robsinson's video about Pappy and the game's inventive play mechanics.
Particularly interesting (and tres Nintendo) are the game's use of "light patterns" — user interface and narrative prompts that encourage the player to haggle with in-game merchants instead of just give Nintendo money:
