Deck of the Balatrones
Weapon, rare (requires attunement)
Each card in this deck has a back with a design of chaotic, multicolored glyphs. When you first find the deck, it has a random arrangement of cards, with a random number of cards in each rank and suit, but it always has 52 cards. When you roll for initiative while attuned to the deck, draw eight cards from it. As a bonus action, you may discard up to five cards from your hand, and then draw that many more from the deck. When you make an attack roll with this weapon, choose up to five cards to make a poker hand with them. The weapon's damage die changes based on the hand you made. All damage below is slashing damage.
- Flush Five - Five cards of both the same rank and the same suit. Base damage: 2d6+6.
- Flush House - A Full House where all cards are the same suit. Base damage: 1d12.
- Five of a Kind - Five cards of the same rank, but not the same suit. Base damage: 1d10+5.
- Straight Flush - Five cards with sequential ranks, and the same suit. Base damage: 1d10.
- Four of a Kind - Four cards of the same rank. Base damage: 1d8+4.
- Full House - A Three of a Kind with one rank, and a Pair with a different rank. Base damage: 1d8.
- Flush - Five cards of the same suit, but not in sequence, not a Full House, and not of the same rank. Base damage: 1d6+3.
- Straight - Five cards with sequential ranks, but not the same suit. Base damage: 1d6.
- Three of a Kind - Three cards of the same rank. Base damage: 1d4+2.
- Two Pair - One Pair of one rank, and another Pair of a different rank. Base damage: 1d4.
- Pair - Two cards of the same rank. Base damage: 2.
- High Card - None of the above hands. No matching ranks, at least one break in the sequence of ranks, and at least one off-suit card. Base damage: 1.
A creature killed by this weapon dissolves into a cloud of red mist.
I'm still trying to figure out how to make individual card scoring, Jokers, Tarot and Planet cards work with this, because D&D notably does not have enemies with 2.9 x 10^13 HP.