The Legend of Zelda: Ocarina of Time 3D Glitches

Walk Through Epona
Become grown-up Link and position Epona relatively close to the broken drawbridge that leads you into the Hyrule Castle Town. Face her parallel with the stream but make sure she's still standing on grass, not stone. If you look at her from a little bit away so that she's standing in front of the bridge, she should be pretty close to right in the center between the two small stone ledges.

Go into Castle Town now and then come right back out and you'll walk straight through her. You can try having Epona in different positions so you walk through different body parts. There's no real point to this but it is interesting.