Why does my freezer suddenly smell?

[FreakoidOrganisoid]

Two days ago it was fine, today I opened it and a disgusting smell came out.

It hasn't defrosted at all, there's nothing ancient lurking in it and the smell seems to becoming from the ice cube compartment rather than any of the drawers.

It really smells vile.

Either you have a blocked drain or a dead mouse down the back.

Is there a dead cow in there somewhere?

There is a steak mooos, but not a whole cow

I put some diced onions in it the day it was fine, could it be those??? It smells kind of like really smelly burps!

Are you sure its down at the correct temp?

I haven't changed the dial but don't know what temp it is actually at. Everything is still frozen though