An additional cost is something you pay on top of whatever base cost youre using (mana cost or alternative cost)
Being able to go off the rails and do a bunch of weird stuff is refreshing in a way, sort of like Marvel's "What If..." series
Acererak the Archlich Calculating Lich Custodi Lich Demilich Dralnu, Lich Lord Ebondeath, Dracolich Everlasting Lich (playtest) Havengul Lich Jarad, Golgari Lich Lord Josu Vess, Lich Knight Kheru Lich Lord Lich Lich Lord of Unx Lich's Caress Lich's Duel Mastery (playtest) Lich's Mastery Lich's Mirror Lich's Tomb Lich-Knights' Conquest Lichenthrope Nefarious Lich Phylactery Lich Scornful ther-Lich Storrev, Devkarin Lich Tomebound Lich Underrealm Lich Varina, Lich Queen Vindictive Lich Zul Ashur, Lich Lord
If I want to drop a Wrath of God, barring a Mystic Snake, you aren't likely to say no, and you can't lean into White for a lot of dorks that give your team indestructible, so your options are more limited
Rat Colony / Relentless Rats Relentless Rats was the first A deck can have any number of cards named X card, which emerged back in Fifth Dawn
The creatures in the deck largely contribute to the tribal theme of the deck being vampires for the most part
