Text (UG+errata): 2/2. ; Denimwalk (If defending player is wearing any clothing made of denim, this creature is unblockable.) [Oracle 2009/07/08]
You are allowed to remove garments in the neutral state before blockers are declared. Removing a garment is played as faster than a mana ability. [QAS 1998/09/09]
Any denim will count, even underwear and shoes. [Barclay 1998/08/13]
Removal of clothing is subject to indecency laws. [D'Angelo 1998/08/17]
Denim is the substance that jeans are made of. [Levis 1998/09/09]
All tournament formats have banned cards from Unglued.