You are a miracle worker if you can identify this film from these details

[ICanWearMyBoobsUpOrDown]

15 year old is trying to remember a film he liked when he was younger. I can't think what it is. He says

A teenage girl meets some sort of slimy monster guy and hides it from her parents. Keeps it in her shed.

She ends up going underground and meeting all of the slimy monster people.

The girl had short blondish brown hair and wore a coat

Does anyone have the faintest idea what it is please.

Angela Carter's Red Riding Hood themed tale ..was v weird ..ah..The Company of Wolves ?

Hmmm ....actually nope thats not it ..

A few details misremembered and you have the opening scenes when Gertie met ET!

Not that one thanks for trying, we are googling everything and going mad just now.

Can he pin it down to a year? What was he wearing/playing with/where living/school/friends?

Not ET, fungus the bogey man, Labyrinth, big foot and the Henderson, Goonies, drop dead fred or water babies

This is so frustrating, and I reckon he's probably misremembered some of it too.

He reckons he was about 7/8 but can't remember if it was an old or new film m then.

I'm asking the impossible I know.

Not BFG either.

Could it be fungus the bogeyman, Raymond Briggs

Skellig? That involves children hiding a man, but not slime and possibly not drains...

Not flight of the navigator either.

The creature was bigger than the girl apparently.

The Spiderwick Chronicles?

Not skellig either

Real life/action or animation?

First thought was Monsters Inc

Yay I got it. It's stig of the dump

Pretty much nothing like the description at all.

Thanks every one.

... although don't think the monsters were slimy!

Stig of the dump!!!!! That was boy with a cave man!

Stig of the Dump?!

Ha ha.