Mime

Effect: Retrigger all card held in hand abilities

Mime in Balatro: Retrigger all card held in hand abilities. Rarity, cost, unlock, synergies, and how to play it.

Cost: $5

Rarity: Uncommon

Category: Other Jokers

Unlock requirement: Available from start.

Verdict

Looks like a nothing card and is the second-largest multiplier in the strongest deck in the game. Buy it in any held-in-hand build.

It retriggers every held-in-hand ability at once — Steel cards, Gold cards, Blue Seals, Baron, Shoot the Moon, Reserved Parking, Raised Fist. One slot doubles all of them simultaneously.
Against Baron it turns X1.5 per King into X2.25 per King. Across five Kings that is 1.5^5 = X7.6 becoming 1.5^10 = X57.7.
Steel cards held pay X1.5 each and are retriggered too, so a Steel King under Baron and Mime is worth 1.5^4 by itself.
It is Uncommon and costs $5, which is absurd for the size of the multiplier it produces in the right deck.

Order-agnostic for its own effect, but if you run a copy joker, Mime is usually the correct thing to copy.

Only buy it once you have something that triggers from hand. Check your board for Steel, Gold, Blue Seals, or Baron first.
Play the smallest hand that clears the blind. Every card you play is a card not sitting in hand being retriggered — High Card, Pair, and Three of a Kind are the natural fits.
Stack hand size. Mime multiplies whatever is in your hand, so hand size upgrades are effectively multiplier upgrades.
If you own Blueprint, pointing it at Mime is usually better than pointing it at Baron — it adds a trigger to every held ability at once rather than to one of them.

Five Steel Kings held: 1.5^20 = X3,325.

Mime doubles both the Baron trigger and the Steel trigger on every King, taking each King from 1.5^2 to 1.5^4.

Each held Queen goes from +13 Mult to +26 Mult.

Shoot the Moon is a held-in-hand ability, so Mime retriggers it per Queen. Note this one is additive, so it must sit left of your X Mult jokers.

Mime does absolutely nothing for cards you PLAY. In a Flush build that empties its hand every turn it is a blank slot.
Buying Mime before you have any held-in-hand effect. It is an amplifier with nothing to amplify.
Boss blinds that shrink hand size hit Mime builds twice, since every lost card is a lost retrigger as well as a lost card.

In a Baron deck this single $5 card is worth roughly 7.6x your total score at the Ante 8 boss.

Mandatory in held-in-hand builds. It is the difference between 1.5^10 and 1.5^20 once Steel is online.