For the older Trekkers among us, this answer is likely to be TURNABOUT INTRUDER.
For others, due to syndication differences, random watching and assorted factors, this might be difficult to verify.
In my particular case, I saw MUDD'S WOMEN last of them all-----''saw'' being watching start-to-finish without skipping any acts or scenes. I had only seen five minutes at a time of it previously. As a younger kid, I may have found it too female-centric to keep watching, but I can't definitely say. But I finally finished MUDD in 1982, about a decade after I saw many of the others. I believe I came to THAT WHICH SURVIVES, DOOMSDAY MACHINE and SPECTRE OF THE GUN later than most for unknown reasons. But I had seen all but MUDD'S WOMEN well before 1978.
I hand the question over to the gang. Which TOS episode completed your set?
For others, due to syndication differences, random watching and assorted factors, this might be difficult to verify.
In my particular case, I saw MUDD'S WOMEN last of them all-----''saw'' being watching start-to-finish without skipping any acts or scenes. I had only seen five minutes at a time of it previously. As a younger kid, I may have found it too female-centric to keep watching, but I can't definitely say. But I finally finished MUDD in 1982, about a decade after I saw many of the others. I believe I came to THAT WHICH SURVIVES, DOOMSDAY MACHINE and SPECTRE OF THE GUN later than most for unknown reasons. But I had seen all but MUDD'S WOMEN well before 1978.
I hand the question over to the gang. Which TOS episode completed your set?