“Dug” is the past tense of the noun “dog”. Something which was a dog, but is so no longer, is now a dug. An example is canine transmissible venereal tumour, which used to be a dog, but is now a cancer of dogs.
The much subjunctive mood of “dog” is “doge”. So amaze.
The ipsapudessive case is “dougal”, but although this has a theoretical existence, there is no situation in which it is correct to use it. This is the significance of Dougal’s name in “The Magic Roundabout”.
The superlative counterfactual is “dragon”.
The affirmative mood is “dig”. A dig is something that certainly is a dog.