Random Shiny on ROM during a Challenge Run

this happened a few days ago now, but recently I decided to take a crack at the Date of Birth Challenge, made up by Bestwaffles on PokeCommunity.
I chose to do this challenge on a ROM of Platinum, since I'm using my physical copies to hunt the starters eventually. the ROM I'm using is almost completely unmodified aside from changing trade evolution requirements, and the odds for shinies are completely untouched. going by the challenge rules, I put my team together and started the file.

in the process of choosing a Pokemon of my assigned color (which was purple, going off of the color classifications in the dex) for one of my team members, I was torn between Crobat and Drifblim. I initially wanted to use Drifblim for this slot, mostly because I've used Crobat in so many other playthroughs, but apparently my file had other plans.
while walking through the Oreburgh Mine to talk to Roark, I found this little goober.

I am not kidding when I say, the first words that came out of my mouth when I saw it were "you're fucking KIDDING" LMAO
I should also add I'm putting this in Hidden Grotto because, even though the odds are unchanged, I was using speed-up at the time just to get things rolling a bit faster. then again, it's not like I was using it specifically to speed up a hunt or anything, but just to be safe.
and since it's still classified as purple in the dex, it's perfectly legal for the challenge! so naturally, I'm using him on my team. good times all around