No idea on who made it, but I have a technical question - how was it made? Blown with mould assistance? Interesting how the spiral pattern on the base continues into the pontil scar. My first guess was that it was blown into the mould with a cup shaped punty, spun to smooth the seam scar, then transferred onto a rod at the base, top finished perhaps in the glory hole. But that doesn't work because it's a spiral and not circle grooves and therefore it couldn't be spun.
So, how'd they do it?