Goat format ruling
Guardian Grarl

Card effect (current official text)Cannot be Summoned unless you control a face-up "Gravity Axe - Grarl". If this is the only card in your hand, you can Special Summon it (from your hand).
Rulings
- If you wish to use Guardian Grarl's effect to Special Summon him from your hand, you still must have Gravity Axe - Grarl on your side of the field.
- You cannot Tribute Summon Guardian Grarl by Tributing a monster equipped with your only Gravity Axe - Grarl on your side of the field, because the Gravity Axe - Grarl will no longer be on the field when the Summon occurs.
- Q: Can "Guardian Grarl" be Set on the field and then flipped by an attack OR by the effects of "Swords of Revealing Light" or "Ceasefire" without having "Gravity Axe – Grarl" on the field? A: Yes, that is correct.
- Q: Can "Guardian Grarl" be Set on the field and then flipped by "Book of Taiyou" without having "Gravity Axe – Grarl" on the field? A: Yes you could. Using the effect of "Book of Taiyou" is not considered Flip-Summon, so it would be fine to do this.
- Q: Can "Guardian Grarl" be Special Summoned with its effect if "Gravity Axe – Grarl" is not on the field? A: The text on "Guardian Grarl" states that "This card can only be Normal Summoned, Flip Summoned, or Special Summoned when there is a "Gravity Axe − Grarl" on your side of the field." You would need to have the "Gravity Axe − Grarl" in play on your side of the field.
- Q: If you had a monster on the field with "Gravity Axe – Grarl" equipped, could you Tribute it to Summon "Guardian Grarl"? A: You cannot Tribute the only monster equipped with Gravity Axe - Grarl to Tribute Summon Guardian Grarl. Of course, Special Summoning Guardian Grarl is fine, if you have Gravity Axe - Grarl equipped to a monster and Guardian Grarl is the only card in your hand. Steve Okegawa, 02/18/04
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.