You all might know about Texture hacks on the 64 Zelda's but this is true work.
Play as Mario in OOT~
MM to OOT object port
Yes thats a custom gun put in OOT
(NOTE: Yes, we can add animations and make it shoot bullets.)
PLAY AS DARK LINK IN MAJORA'S MASK
Yes sir, that is play as Samus in OOT
Talk to enemies
OOT to MM map port
Lets enter the matrix
Play as Samus:
Majora's Mask Deku to Ocarina of Time:
More random videos:
TRIFORCE IN OOT:
If you view more of Flotonic's videos you will see he has more play as's and all kinds of other mods.
All of these mods where done by members of a site called MACO.