When a sheep gets stuck in a bramble patch it just stands there, possibly until it dies, if no-one rescues it. First thought is 'stupid sheep', but now I know it's 'clever bramble'
I was attacking my fruit garden yesterday, where the bramble patch has been untamed for at least three years. Within minutes I was well and truly trapped and could only get out because I had my loppers. I realised that brambles have a neat trick of rooting their tips so they are firmly attached at each end of the stems, forming a very spikey loop. After just three years those loops are interwoven and almost impenetrable, apart from to small creatures such as rabbits, blackbirds and terriers.
So the bramble's plan is: wait for passing sheep (or human); stick out a spikey stem and hook onto the wool (clothing); as the sheep (human) initially struggles whip in a few more stems, wrapping around the legs, body and head, preferably finding some bare bits of tender skin; sheep stands still til it dies; body decomposes and bramble has a tasty supply of rich food

If on the other hand, it's caught a human then it gets chopped down - but you can't win 'em all
There are plenty of carnivorous plants, such as Venus' Fly trap, Pitcher plants and Triffids, but it's only now I realise that the humble bramble is one too. Thank goodness I had my loppers