The original ATK of “King of the Skull Servants” is determined by its effect. This is further doubled/halved by “Megamorph” and other effects that are based off of original ATK. If the number of “Skull Servant” and “King of the Skull Servants” cards in your Graveyard changes, re-calculate the original ATK of “King of the Skull Servants”, then re-apply the effect of “Megamorph”. If you have “King of the Skull Servants” with an original ATK of 2000 (2 “Skull Servant” cards in your Graveyard), and you equip it with “Megamorph”, its original ATK will be 4000 when your Life Points are lower, and 1000 when your Life Points are higher.
Since the ATK of this card is ?, it cannot be Special Summoned by the effect of “Mystic Tomato”.
Removing from play 1 “Skull Servant” or “King of the Skull Servants” to Special Summon a “King of the Skull Servants” is a cost.