They've only been around for the last 20 years or less, a stowaway from China.
https://en.wikipedia.org/wiki/Brown_...ated_stink_bug
I had heard that they really stink if startled or injured and while I have seen a few in the house I never had a problem with gently grabbing them in a tissue and throwing them outside, kinda thought that their 'stink' was a bit exaggerated. But...while I was outside last year I accidentally crunched one and phewwwww...and this was outside and it was still terrible.