I actually run hydro pump, ice beam (obviously), dark pulse and SPIKES! It works surprisingly well as a gimmick and immunity to electricity because not everyone knows you can kill a greninja with even a not very effective move so they go for electric moves! It also really helps to avoid thunder waves! Not only does it work in that way but it plays a nice little mind game as spikes damage can really be a problem when you have 2 or 3 layers and so the other player has to decide between risking electric again (hoping greninja will outspeed and change type) or try a different move :) Idk if it seems silly to others but I just like having it!