Any ideas how this could have happened?

Tonyandthewhale

First off, can you see the picture there? I'm rubbish with computers and chances are it didn't upload properly.
Secondly, if the picture does work, has anyone ever seen anything like this before? It's the plate in my rear deraileur that holds on the jockey wheels but it's got a big gash torn in the side of it as if yer man wolverine from the X men was at it.
The damage was done when I a friend of mine borrowed my bike for a charity cycle and it's bugging me trying to figure out how he managed to feck it up like that.
It doesn't look like it was crashed since the damage is isolatated to the inside deraileur plate thing and surely the chain-stays/wheel would be damaged if an external force was applied to the derailleur like that. Could a dropped chain some-how have mangled it?
Needless to say the afore-mentioned friend is playing dumb and I'm going mad trying to figure out how he managed to mess it up so badly in the short while he had it.

Piste

Pic isn't showing for me, sorry.

Golfanatic

Can't see the picture but bring it into a bike shop anD they will probably know

Tonyandthewhale

Yeah, I tried sending it as an attachment but I got a "service unavailable" message, I'll try again later. I will bring it into the shop but won't get a chance for a few days and it's annoying me now as it's sort of a mystery how it could have happened.

SugarHigh

www.imageshack.us

Easy to upload there and then just post the url it gives you