BT San 96a(52)var. :דאשתני אפיה ואידמי לכלבא‏ : his face changed and became similar to the shape of a dog [or: read with a further variant: עקובה, i.e. rear end!]
See the entire entry for ˁuqqāḇ, ˁuqqāḇā v.n.D investigation