So did his third head get replaced with an energy railgun?
EP19-JP060 対壊獣用決戦兵器メカサンダー・キング TaikKaiju You Kessen Heiki Mecha-Thunder-King (Super Anti-Kaiju War Machine Mecha-Thunder-King)
Level 9 LIGHT Machine Effect Monster
You can only use the 4th effect of this card’s name once per Duel.
(1) During the Main Phase (Quick Effect): You can discard this card; banish 1 “Kaiju” monster you control that is owned by your opponent, then, you can Special Summon 1 monster from your GY.
(2) You can only control 1 “Kaiju” monster.
(3) This card is unaffected by other “Kaiju” cards’ effects, also it cannot be destroyed by battle with a “Kaiju” monster.
(4) During your End Phase, if this card is in your GY: You can Special Summon this card.