Does FIGHTing with no hitting do the same thing as SPARE?

I seem to recall that when I use the FIGHT command, and let the targetting bar go past the whole screen and off of it without pressing Z, the effects seemed to be similar to the results of the SPARE command, at least during the boss fights where SPARE is not a game ending button. Is it always the case? I haven't tested it on regular monsters, where SPAREing one would end the fight.

Solution 1:

It's very similar, but not quite the same. From the Undertale wiki:

Allowing the bar(s) to slide all the way across the meter results in them fading out, and a miss. This method is equivalent to selecting Spare, except that it does not cause any monsters to leave the battle, even if the Spare text is on.