While the occasional resolution of this card does fail (resulting in a Sad Naus, if you will), Ad Nauseam is the best Black card in competitive Commander format
On the turn a character comes into play, their Ink needs to dry, so they cant challenge, quest, or use abilities that require them to exert
Strong job select cards like Dragoon's Lance and Samurai's Katana have steep equip costs, which you can offset with this
Badgermole Cub only gives you the extra mana side but it does come packaged with its own mana dork thanks to Earthbend
In the extremely unusual case where the mana value of one or more of the targets changes while you're paying costs, the cost to cast Urgent Necropsy, including the additional cost, remains what you previously determined