The move Struggle - available when no other move can be used, usually because no move has any PP - can be seen as worse.
It deals as small bit of damage (a typeless move of 50 power) so does help you but you receive recoil damage equalling 25% of your overall HP.
I have forced opponents to use struggle in competitive battles which has won me the game as my Pokemon was poisoned and was a staller with no attacking moves. If the opponent was forced to use struggle (which it can't - this is hypothetical) then I would have lost as they was no way that I could damage it [I could have used toxic but I was badly poisoned].
Genrally speaking Splash is the worst move as it has no effect whatsoever.