Played on an original N64 PAL cartridge with the Expansion Pak, this is something that accidentally happened to me in a speedrun that I recreate here to show how it works ;) I was gobsmacked when I fell through 90 feet (!?) of "solid water" and the cutscene plays everything and land right at the bottom! I played around with it a few times and it consistently works! Then a few days later while looking up something to do with the Spirit Temple I saw a link about Farore's Wind and can child link warp to adult sections or reverse etc, that led me to the Water Temple page (was just reading stuff) and saw that this idea has been used in speedruns! This made me want to upload this - So it's not an original idea, but when I'd recorded it the first time it was an unknown to me, very unknown, and VERY random!
If anyone has random stuff they found in N64 games feel free to link your own recorded uploads in the comments section :)
The Legend of Zelda: Ocarina of Time Statistics For harKazoid86's N64 Hub
Currently, harKazoid86's N64 Hub has 1,191,004 views for The Legend of Zelda: Ocarina of Time across 54 videos. This game accounts for over 1 day of watchable video on his channel, or 19.11% of the total watchable video for The Legend of Zelda: Ocarina of Time on harKazoid86's N64 Hub's YouTube channel.