Heart of Gaia (MZMU-EN033) - Maze of Muertos 1st Edition

(This card is always treated as a "Millennium" and "Gaia The Fierce Knight" card.)
If a Level 5 or higher Monster Card is on the field, you can Normal Summon this card without Tributing. The Level of any monster your opponent Normal or Special Summons in Attack Position, while this card is in your Monster Zone, is increased by 7. When your opponent activates a monster effect (Quick Effect): You can send 1 other face-up Level 5 or higher Monster Card you control to the GY; negate the activation, and if you do, destroy that card. You can only use this effect of "Heart of Gaia" once per turn.