Hypothetically speaking if there were an ability and/or move

>>33337308
>Set: double battle
>Pokémon: Sylveon, Hydreigon vs. Dragonite, Oldtimey (has the retrograde ability, psychic/ghost type)
>Oldtimey's retrograde! things went back to the stone age!
>Turn 1: Dragonite used Outrage! foe sylveon ??? -- Sylveon used shadow ball! foe oldtimey ???
>(still)Turn 1: Hydreigon used bite! foe oldtimey ??? -- Oldtimey used amnesia! oldtimey's ??? rose

What happens in each one of those ???s ? Did hydreigon get STAB on the bite?

Btw retrograde is overconvoluted and cancerous either in move or ability form, let's settle that right now. Just wanting to know the details about cases like the above.

>>33337498
I am well aware the Retrogade is incredibly convoluted, but it's an interesting prospect. Now to answer your questions.
For the first ???, Outrage would still have no effect on Sylveon as that is how the Fairy-Typing operated, the move/ability won't change types if there was no type change beforehand (ergo Sylveon remains a Fairy-Type as Sylveon was always a Fairy-Type).
For the second ???, Shadow Ball would again have no effect as in Gen I Psychic was immune to Ghost-Type.
For the third ???, Bite would have no effect as Bite would become a normal type move and only have a 10% flinch chance, so Hydreigon would no longer get STAB (however if a move that was always Dark-Type was used, like Crunch, it would remain a Dark-Type and Hydreigon would get STAB on it).
And for the fourth ???, for all cases where the move originally affected the SPECIAL stat in Gen I, it will apply to both the Special Attack and Special Defense stats, so oldtimey would raise both Special Attack and Special Defense by two stages.

>>33337667
>And for the fourth ???, for all cases where the move originally affected the SPECIAL stat in Gen I, it will apply to both the Special Attack and Special Defense stats, so oldtimey would raise both Special Attack and Special Defense by two stages.
See this is what I was talking about. Fucking oldtimey should get banned.

Jokes aside, the main problem with retrograde, even ignoring how convoluted it is battlewise, is that it has to be permanently and heavily upgraded and checked every new gen for the rest of time. Whatever intern gets punished with coding this move/ability would have to build it in such a way that retrograde somehow is able to know what a move's previous effect was, even if said old effect is no longer in the current game because the new effect is coded instead, which would inevitably lead to the need of creating an ever-growing database just for this one move to know if roar has negative priority or not. It is a waste of resources before it is a cool move/ability.

If you look past all that, sure, it would lead to some pretty unique strategies, specially in doubles I would assume. Retrograde wrap, roar and OHKO moves on fast mons would probably get banned, for starters.

sturdy goes back to being ass and talonflame comes back from the dead

>>33337855
Hence why I said hypothetically, as I understand that realistically it's just too much coding for one move/ability to have. Also you're forgetting one little thing for Retrograde Roar
>In a Trainer battle, Roar has no effect

>>33337855
>ever-growing database
Each move would simply have a standard function and retrograde function don't be stupid it could easily work it's 2017

Trapping attacks would be nightmares.