>>299487904
Practical effects can be used to make anyone look like almost anyone else, but it's not as simple as slipping on a mask. If you wanted to go for the absolute highest quality, it'd probably be comprised entirely of makeup and partial facial prosthesis to augment the shape of the face, since a "mask" would never be able to move convincingly. However, that's the kind of stuff that requires sitting in a studio makeup chair for 8 straight hours.
For something like an Internet video, it's much simpler to just use digital trickery.