Crackling, low-budget synth pads filling a quiet house. Five Nights at Wario's 3 on PC is a fan game that somehow nails the feel of being trapped in a haunted home with Nintendo characters who want you dead. Each room gets its own intro track, and they all carry this VHS-era horror cheapness that works perfectly.
Read more
The Summoning Musicbox is genuinely chilling, a simple melody looping while everything falls apart around you. Mario Approaching is just... dread in audio form. You hear it and you know something bad is coming down the hall.
Toad's Diary adds this weird narrative weight. The Ambience tracks are sparse but effective, just enough sound to remind you that you're not alone. For anyone curious what Mario horror sounds like at 2AM with the lights off.