Called an 'Knock-U-Out' potion by Roper Klacks, this smoke bomb incapacitates anyone unlucky enough to be caught in the blast. Apparently it also comes in a drinkable form. After Crow brings her the smoke bomb, Zoë Castillo uses it on Dagdam Yiru to escape Friar's Keep.
Obtained from Roper Klacks' potions stall in the Magic Ghetto.