Spinda is only available on the Switch in Brilliant Diamond and Shining Pearl. But, ILCA programmed Spinda differently than in every other generation beforehand. So, if you tried to put a Spinda in or out of BDSP to Home, it would have completely different spots than every other game. So, the solution they landed on was to just NOT let you move Spinda in or out of BDSP at all. So, Spinda is basically locked away on Home, limiting you to ones you already have from previous generations. Which has made Spinda oddly desirable, since you can't complete the Home Dex without one.
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