Wattcube

Equip Spell

Equip only to a Thunder-Type monster. It gains 100 ATK for each Thunder-Type monster in your Graveyard. You can send this face-up card from the field to the Graveyard to have 1 face-up Thunder-Type monster you control gain 1000 ATK.

Rulings – Yugipedia

Printings:

The Shining Darkness: TSHD-EN054 (Common) - 2010-05-07

Prices:

Cardmarket: 0.12 €
TCGplayer: $ 0.44