Mist Valley Thunder Lord

Level 7 WIND/Thunder Synchro Effect
2600 ATK / 2400 DEF

1 Tuner + 1 or more non-Tuner "Mist Valley" monsters
Once per turn, you can select 1 card you control. Return it to the hand, and this card gains 500 ATK until the End Phase. This effect can be activated during either player's turn.

Rulings – Yugipedia

Printings:

Duel Terminal 2: DT02-EN090 (Duel Terminal Ultra Parallel Rare) - 2010-05-25
Hidden Arsenal 2: HA02-EN060 (Secret Rare) - 2010-07-15
Hidden Arsenal: Chapter 1: HAC1-EN063 (Common) - 2022-02-24
Hidden Arsenal: Chapter 1: HAC1-EN063 (Duel Terminal Normal Parallel Rare) - 2022-02-24

Prices:

Cardmarket: 0.13 €
TCGplayer: $ 0.07