Makes you look like your ghosts! :o
I like my textures too much for this, but I must admit it's cool.
Are you talking about the opacity present in mods like aikido-doa.tbm?
The walls are translucent in the replay and they look so during the match too, but they block out the tori's, making the game really difficult, which is a shame, as I have found a very fun gamemode in there.