I found a small black beetle under a plastic pot that has been in the same place all winter. The beetle had a gold-colored head. I tried to kill it, but it walked quite quickly. I wounded it, and finally, I heard its exoskeleton snap. I killed it because I niver saw one like it and didn't know if it was a pest. I tried to identify it on the internet, but couldn't. It was about a half inch long and smooth. Would you know what type of beetle this was and if it is a pest?.
That sounds just like a ground beetle, which is a beneficial insect that is a predator of pest insects. https://extension.umd.edu/hgic/insects/predatory-beetles
Next time you might want to send us a photo before you get rid of something new you see. It may be something good!