These two went from bitter rivals to respectful friends. Here are all scenes of Nintendo / Mario and Sega / Sonic insulting and honoring each other.
List
Alex Kidd in Shinobi World - Mari-oh
Earthworm Jim: Special Edition - DK Mask
Donkey Kong Country 2 - No Hopers
Super Mario World 2: Yoshi's Island - Harry Hedgehog
Astral - Ugly Mario Sprite
Super Mario RPG - Possible Eggman Painting
Segagaga - Nintendo & Mario namedropped
Mario's 20th Anniversary - Sonic with Mario's hat
Super Smash Bros. Brawl - Sonic cutscene
Donkey Kong Country 2 Remake - No "No Hopers"
Sonic Adventure DX - Mushroom item
Mario Kart 8 Deluxe - Sonic costume
Yoshi's Woolly World - Sonic Yoshi
Super Mario Maker - Sonic Mystery Mushroom
Sonic the Hedgehog (Mobile) - Mario reference
Super Smash Bros. Ultimate - Palutena's Guidance
Mario & Sonic at the Olympic Winter Games - Official Crossover
Super Mario-kun - Sonic crossover
Sonic Lost World - Yoshi Zone, Zelda Zone
4K 60fps Gameplay Recorded and Edited by Nintendo Unity.
Friends
Gaming Evolution: www.youtube.com/GamingEvolutionX