Ettore "Mr. Bist" Ferro is the man behind BIST and the winner of the Best Mod contest at the 2009 World Yo-Yo Contest with a yo-yo called Stradivari.
He is known for modding extremely bizarre and creatively conceived yo-yo mods and original designs, including the Tondo (a square aluminum yo-yo).
His youtube channel is here Mr. Bist is widely considered to be insane.
Ettore Ferro aka Mr. Bist