Black Clock Beetle I think, some info: https://www.ukbeetles.co.uk/pterostichus-madidus
I read the second word of your comment very wrong
As did everyone else who spends too much time online.
Totally understandable, given how awesome black cloaks are.
Bit blurry but either a type of rover beetle or a beetle larva.
It seemed like a larva, it was pretty translucent. The question is: what kind of beetle?
According to Google Lens it's a Great Diving Beetle larva. Cannot verify.
EDIT - tried again, and this time it says it's a Rove Beetle. So I wouldn't put toouch faith in either result tbh.
What is this thing?
Let us help you identify that mysterious object you’ve found.
Currently in CHALLENGE mode: If you've got something obscure knocking about, post a picture, and let's see how we do. Please prefix such posts with "CHALLENGE:" so we know we've got a fighting chance.