The Winged Dragon of Ra

This card cannot be Set. This card can only be Tribute Summoned by Tributing 3 monsters. The Normal Summon of this card cannot be negated. When this card is Normal Summoned, Spells, Traps and other monsters' effects cannot be activated. While this card is on the field, control of this card cannot switch and it is unaffected by the effects of Spell Cards, Trap Cards and other monsters. The effect of “The Winged Dragon of Ra” only affects this card for one turn. When this card is Special Summoned from the Graveyard, it is sent to the Graveyard during the End Phase. This card can always attack during the turn it is Summoned. This card’s ATK and DEF are equal to the combined ATK and DEF of the monsters Tributed to Summon it, respectively. Once per turn, you may pay 1000 Life Points to destroy all monsters your opponent controls. You can Tribute monsters in order to increase this card’s ATK by the Tributed monsters’ ATK. You can pay any amount of Life Points in order to increase this card’s ATK by the amount of Life Points paid. If you use this effect, you can send one "De-Fusion" in your Hand or under your control to the Graveyard in order to reduce this card’s ATK to 0 and increase your Life Points by this card’s prior ATK. You can activate this effect at any time. During either player’s turn, you can pay 1000 Life Points to transform "The Winged Dragon of Ra" into its Phoenix Mode. Until the end of the turn this effect is activated, the ATK and DEF of this card are reduced to 0 (The ATK and DEF of this card return to their respective values prior to this effect‘s use) and it gains the following effects: ● This card cannot be destroyed by battle, and you take no Battle Damage from battles involving this card. ● This card cannot be targeted and is unaffected by the effects of other monsters, Spells, and Traps. The effect of “The Winged Dragon of Ra” only affects this card for one turn.

Anthony phoenix mode means that all other cards are destroyed. So when it goes to phoenix mode its basically a effect destroying all other cards.