Golden Freddy is a minor character in the SMG4 series.
He originates from the game Five Nights at Freddy's. He is a mysterious animatronic who crashes the game when he kills the player in the original game, while simply functioning as a jumpscare in Five Nights at Freddy's 2.
He makes his first (albeit minor) appearance in R64: Freddy's spaghettiria. In the episode, he appears in Mario's office and offers him spaghetti (which is impossible in the actual FNaF as he doesn't move in the original game). When Mario tries to eat the spaghetti, he crashes the game using Toad's face instead of his own. Mario then travels through a hallucination where he is Foxy in the pizzeria during the morning, who then bites Toad's frontal lobe off for annoying him (a reference to the Bite of '87).
Golden Freddy makes a possible cameo appearance in R64: Return to Freddy's Spaghettria, where Toy Freddy pulls a lookalike suit and throws it at Mario, but the latter escapes. Tthe suit is not seen again for the rest of the blooper.
Golden Freddy also makes a cameo appearance in R64: Revenge of Freddy's Spaghettria, in which he appears in the Phantom Animatronic Lounge along with the Other Phantom animatronics. He appears in its FNAF 2 render when he throws a potato at Balloon Boy and tells him to "just shut the f*ck up!"
Golden Freddy, along with many of the other animatronics, would also appear in SMG4: Freddy's Ultimate Custom Spaghetteria.