Hello,
I think this was one of two all-black spider-hunting wasps
Anoplius nigerrimus I was watching dashing in and out of crevices in the cliff face at Yaverland, IoW on Friday.
I lost track of both until one reappeared in the jaws of a spider - evidently it had met its match. The spider carried it off, held high by the head like this. I followed it for a while then lost it.
Are spider-hunting wasps often this unlucky? Is there a particular spider that preys on them, I wonder?
Thanks for looking,
Rob