Fuschias Died Suddenly

I recently found that two of my prized fuschias suddenly died. They seemed to dry out, despite watering, and all the leaves dropped off them and they died.

The only possible strange thing I found was a super sized slug that I found under two of the pots. The slugs were massive and you could see their eyes. Never seen anything like them before.

Any ideas?

 

Maybe they ate the bark off near the base. Not saying this is usual, but as you say they WERE present to arouse suspicion. Garden slugs hiding under a pot usually are up to something.