Cipher Interference

Continuous Spell

During damage calculation, if your "Cipher" monster battles, while another monster with its same name is on the field: You can double the ATK of your battling "Cipher" monster until the end of the Battle Phase. You can only use this effect of "Cipher Interference" once per turn.

Rulings – Yugipedia

Printings:

Brothers of Legend: BROL-EN039 (Ultra Rare) - 2021-12-02

Prices:

Cardmarket: 0.10 €
TCGplayer: $ 0.12