Anyone ever heard of a spontaneous rose bush growing? [View all]

I am 95% sure a sucker rose bush is growing off my existing rose bush. I understand suckers and runners on plants, and the leaves certainly look like roses. I'd love to have this bush spread out as much as possible right now so I'm going to leave it be.

But now, in a completely different part of the yard, in the flower beds I just created from scratch, another bush-type thing appears to be growing, and I swear it's the exact same plant! I've never heard of rose bushes growing spontaneously like that and when I search google under "spontaneous rose bush" I don't get anything aside from occasional hits about suckers and runners. AFAICT, it's almost impossible to grow them from seed.

Have any of you ever heard of such a thing happening, a rose bush just growing spontaneously?