20 years ago this week, Mario Tennis was released for the Nintendo 64 in Japan. Excluding 1995's similarly named Mario's Tennis for the Virtual Boy, Mario Tennis was the very first in the series we know and love today, but it also introduced something far, far more important.
Yes, Mario Tennis introduced Waluigi to the world, Wario's mischievous pal and arch-rival to Luigi. Since then, he's gone on to appear in countless Mario spin-off titles - you'll find him in most sports games, the Mario Party series, and the Mario Kart series - and while he's never truly starred in a main series game, you'll still often find little cameos such as the Waluigi outfit that appears in Super Mario Odyssey.
The character has had a pretty mixed reception over the years, with some critics originally believing him to be a cheap, unimportant 'knockoff' of sorts from the main cast, but he's also gained something of a cult following. Overly passionate fans have been singing Waluigi's praises for years, and while some have taken things way too far in recent times, Nintendo has described Waluigi fans' passion as "fantastic".
Either way, it'd be weird to see a Nintendo sports game without him nowadays, and the relationship between Mario, Luigi, Wario, and Waluigi is one we'll never fail to enjoy.
Here's to another 20 years of Waluigi madness. Wah.