Edison format ruling
The Earth - Hex-Sealed Fusion

Card effect (current official text)You can substitute this card for any 1 Fusion Material Monster, but the other Fusion Material Monster(s) must be correct. You can Tribute Fusion Material Monsters on the field, including this face-up card; Special Summon 1 corresponding EARTH Fusion Monster from your Extra Deck.
Rulings
(1) You can substitute this card for any 1 Fusion Material Monster. The other Fusion Material Monster(s) must be the correct one(s). (2) By Tributing Fusion Material Monsters on the field, including this card, Special Summon 1 EARTH Fusion Monster from your Fusion Deck.
- The (1) effect does not have any classification. It is not an Ignition, Trigger, Quick, or Continuous Effect.
- This effect does not target.
- Using The Earth - Hex-Sealed Fusion as a Fusion Material does not start a Chain Link.
- This effect does not apply if The Earth - Hex-Sealed Fusion is in the Deck / removed from play.
- This card cannot be sent to the GY to Special Summoning Chimeratech Fortress Dragon or XYZ-Dragon Cannon.
- If The Earth - Hex-Sealed Fusion is named by Prohibition, you cannot use its effect.
- The (2) Ignition Effect activates & resolves on the field.
- Tributing this card and the legal Fusion Material Monster(s) on the field is a cost.
- This effect does not perform a Fusion Summon, so it can activate while Non-Fusion Area applies, but it cannot Special Summon Evil Hero Dark Gaia or Ultimate Ancient Gear Golem.
- The Fusion Monster Summoned by this effect cannot be Special Summoned from the GY / removed from play, since it was not properly Fusion Summoned.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.