Megarock Dragon

Level 7 EARTH/Rock Effect
? ATK / ? DEF

This card cannot be Normal Summoned or Set. This card cannot be Special Summoned except by removing from play a Rock-Type monster(s) in your Graveyard. The original ATK and DEF of this card become the number of Rock-Type monsters you removed from play when you Special Summoned this card x 700.

Rulings – Yugipedia

Printings:

The Lost Millennium: TLM-EN015 (Super Rare) - 2005-06-01
The Lost Millennium: TLM-EN015 (Ultimate Rare) - 2005-06-01
Structure Deck: Invincible Fortress: SD7-EN012 (Common) - 2006-05-15
Dark Revelation Volume 3: DR3-EN195 (Super Rare) - 2006-11-25

Prices:

Cardmarket: 0.70 €
TCGplayer: $ 0.32