I've been having a google but can't find what this is. Hoping someone here will recognise it and be able to help :)
It looked shiny black with a green sheen, quite slow moving and can roll up. About a cm long
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I haven't seen anything like that before. :o
I hope someone else can id it for you. If not, why not feed it with the leaves of the plant you found it on and see what develops. It looks to me like a larva of some sort of beetle.
I just thought it was a beetle as its got 6 legs, but I may be very wrong ;D
I didn't like to keep, so may never know :-\
Bloody Nose Beetle larvae maybe ?
I agree, some kind of beetle larva, and I think dot has it right as bloody nose beetle. See here (http://www.arkive.org/bloody-nosed-beetle/timarcha-tenebricosa/image-A7234.html).
(http://cdn2.arkive.org/media/E6/E6161CE3-5742-4E2F-87C0-C46ABC644578/Presentation.Medium/Bloody-nosed-beetle-larva.jpg)
After the larval stage the beetle looks like this.
http://www.futura-sciences.com/galerie_photos/data/574/Timarcha_tenebricosa_3.jpg
Thank you all, it certainly looks like a Bloody Nose beetle larva stage. Much appreciated :)