Fairy?

[Buster's Uncle]

That sounds right.

Rusty's got something with the Macwhatsis.

[Rusty Edge]

Actually, you were closer with "Hawser"

http://cryptidz.wikia.com/wiki/Jenny_Haniver

[Unorthodox]

Actually, you were closer with "Hawser"

http://cryptidz.wikia.com/wiki/Jenny_Haniver

Maybe you're thinking the various angel/devil/alien (depending on where and how old) corpses made from rays and cuttlefish? 

I had no idea they went so far back. 

[Buster's Uncle]

There's some Scottish/pseudo-Scottish-sounding term that was current, too, sometime in the age of sailing, possibly up through Victorian, I'm pretty sure.

I've learned over the years to pay serious attention when something tries to pop out of my subconscious, so Molly sawdust is probably something garbled, too, related to the Mcsomething or not.