Did Azumarill's tail ever glow before XY or was that just added to justify its Fairy typing?
Little known fact: Azumarill's tail is actually it's eye, and the rest of it's body is a fake to attract it's prey
>>25879224
Little known fact: Wobbuffets tail is actually it's real body, and the rest of it's body is a fake to attract it's prey
>>25879262
Little known fact: Wurmple's butt-spike are actually it's and the rest of it's body is a fake to attract it's prey
>>25879202
That might have just been inspired by the anime making appendages glow for attacks.
Not outside of the anime, but I doubt it was added to justify fairy typing.