How do you get the purple Yoshi?

Excuse me, but I was wondering if you could shed some light on how one might acquire the elusive purple Yoshi in this game? I've been trying to unlock it for weeks now, but it seems to be quite a challenge. Could you perhaps share any tips or strategies that have proven successful for other players? Or perhaps there's a specific level or achievement that needs to be completed first? I'm eager to learn more about this enigmatic character and how to add it to my collection.