Glam: "This card has Replay once per combat." The first time you play a Glam card in a combat, it is played twice.

What the replay spends

You pay for the card once, before it is played. X is set at that moment and kept for every play of that card, so the replay uses the same X and costs nothing more.

Example: Whirlwind with Glam, played with 3 energy, deals 5 damage to all enemies 3 times, then again 3 times: 6 hits for 3 energy. The next time you play it that combat, Glam no longer adds a replay.

Star-cost X cards work the same way: Stardust with Glam spends your Stars once and uses the same X on both plays.

X-cost cards

CardCharacterEffect per play
WhirlwindIronclad5 damage to all enemies X times
CascadeIroncladPlay the top X (X+1) cards of your draw pile
SkewerSilent8 damage X times
MalaiseSilentEnemy loses X (X+1) Strength and gains X (X+1) Weak. Exhaust
TempestDefectChannel X (X+1) Lightning
Multi-CastDefectEvoke your rightmost orb X (X+1) times
DirgeNecrobinderSummon 3, X times; add X Souls to your draw pile. Exhaust
EradicateNecrobinder11 damage X times. Retain
Heavenly DrillRegent8 damage X times; X is doubled if it is 4 or more
StardustRegent (Stars)5 damage to a random enemy X times
VolleyColorless10 damage to a random enemy X times

Where Glam comes from

SourceEffect
Glitter (Nonupeipe)All card rewards are enchanted with Glam
Silken Tress (Neow)Lose all gold; all cards in the first card reward are enchanted with Glam

See Slay the Spire 2 enchantments.