>>14444870This actually makes sense if you're taking evolution somewhat literally.
Growths like spikes could be used to make a threat display more intimidating, which would improve chances of survival.
Totally not the reason it happens, but still an interesting bit of info.
>>14445317No, you can trade stones. That's what I meant.
Trade the Pokemon or trade the stone, it really doesn't matter. Just depends on what you want in the end.