What kind of spider jumps on the back of a bold jumper and takes it out???? I've never seen this.. They were face to face and this other spider quickly got on the bold jumpers back and annihilated it. It's was barely even larger than the jumper. SW Washington
It most likely is a stealthy ground spider (family Gnaphosidae) - see https://spiderid.com/spider/gnaphosidae/scotophaeus/blackwalli/
for an example. These are active hunters that do not spin a capture web.
I have never seen another spider take out a jumper like that. That was very unexpected. I'm thinking it is a mouse spider.
