For this cheat you need to build a base (Soviet). And then try to find a crate wich gives you a Soviet Construction Vehicle. Then make the Soviet base (Barracks, War Factory and Battle Lab). When you look at the infantry tab you can see Yuri Prime. This is just a normal Yuri but it can Hypnotise people at greater distances and has a bigger Psi Wave.

I am not sure if this also works for Soviet base and get some special Tanya or something.