The only Raiden sprites in MK3, UMK3, and MKT (for PSX and not N64 because Nightwolf juggles axes in N64) are the pose frames. In SNES you could beat up on the Raiden and Arcade Machine, and sometimes Nightwolf's axe would get stuck. This happens in 2nd round 1 button fatalities, I believe DreemerNJ can give more specifics about this because I didn't play around with it after finding it.

I believe it was second round MK3 for SNES. You do a one button friendship with Nightwolf but the opponent is able to still move. The opponent should run up and uppercut the arcade machine so it pops with like 2 drops of blood.

After that its possible to beat up raiden. He remains unmoving, his sprite never changes, but blood comes out and you hear nightwolf's grunts.

Sometimes you can actually start fighting back. Raiden stays the same, but you can start punching, kicking, axing and arrowing with Nightwolf. He can't move or jump, just attack while stuck behind Raiden. When this happens you see the shape of nightwolf behind raiden doing the moves but the sprites are colored the same as the axe or arrow, all green.

Yeah i have that game once ;)) i cant believe that i forgot about the one button fat and the second round thing.. lol