Big old Mug

Its huge & looks like a drain pipe converted to a mug.
Definely a man made this me thinks..nothing girly about it.
My friend & I were Op shopping together & she spied it first, its taken me 6 years to talk her out of it!. probably not worth alot but definately worth the wait.!
Does any one know this backstamp?

Such a hard case old mug !
It looks like an amateurish first off attempt ....
wacky handle reminds me of a cardboard cutout heheee
Can't make head nor tail of the backstamp, which is a pity really.