I like a bit of silly and this was certainly a bit of silly.
An inexperienced wizard is employed to cast a spell to help the fishermen catch lots of fish, instead the spell wakes up a nasty demon who has been trapped for a very long time under the sea. The demon's form is a massive slug that eliminates anything it slimes over.
With the freedom fighter rabbits, the wizard and his dwarf friend banished from Camelot and the inhabitants of Redbrush Hall, this is a great cast of characters. The nasty shape-shifting slugs need to be beaten, but none of the heroes are aware that there is any enemy.
My favourite characters were the rabbits and I loved their "rebel names". And this book has my favourite line ever in it. If you've read it, it's the "sym" bit.
So yes, this book is silly and a bit childish at times, but I found it wonderfully fun to read. I came across it by accident, I think the cover is a bit rubbish, but I totally recommend giving it a go and I'm going to read the next ones.