Paleozoic Eldonia

 This card derives its name from Eldonia, a genus of extinct Cambrian animal found as fossils in the Burgess Shale Formation in the Canadian Rockies of British Columbia, Canada.

---

OCG Rulings

---

The effect "Target 1 face-up monster on the field; it gains 500 ATK and DEF until the end of this turn" is the effect resolution of the activation of the card "Paleozoic Eldonia". (The effect targets 1 face-up monster in either player's Monster Zone.): Paleozoic Eldonia

If the card "Paleozoic Eldonia" is activated during the Damage Step, it can be activated from the start of the Damage Step until before damage calculation.

The effect "Once per Chain, when a Trap Card is activated while this card is in your Graveyard: Special Summon this card as a Normal Monster (Aqua-Type/WATER/Level 2/ATK 1200/DEF 0). (This card is NOT treated as a Trap Card.) If Summoned this way, this card is unaffected by monster effects, also banish it when it leaves the field" is activated in the Graveyard and makes a Chain Link. (It cannot be activated during the Damage Step.)

The effect "Special Summon this card as a Normal Monster (Aqua-Type/WATER/Level 2/ATK 1200/DEF 0). (This card is NOT treated as a Trap Card.)" does not target. It is activated directly in Chain to the activation of a Trap Card. (It cannot be activated in Chain to the activation of a Trap Card's effect.)

The effect "banish it when it leaves the field" does not make a Chain Link.

Mentions in Other Rulings

Paleozoic Opabinia: Normally, a Trap Card must first be Set and cannot be activated until the start of the next turn, but while the effect of "Paleozoic Opabinia" is applying, you can activate "Paleozoic" Trap Cards directly from your hand without having to Set them first. (Note that you can still Set "Paleozoic" Trap Cards from your hand, but you will not be able to activate them until the start of the next turn as usual if you do.) If the effect of "Paleozoic Opabinia" is applying, you can activate "Paleozoic Eldonia" from your hand as if you were activating a Spell Card, by placing it in a vacant Spell & Trap Zone. The effect that targets 1 face-up monster on the field and increases its ATK and DEF by 500 until the end of this turn is applied normally. (Afterward, "Paleozoic Eldonia" is sent to the Graveyard.): If "Paleozoic Eldonia" is activated from the hand by the monster effect of "Paleozoic Opabinia", how is it activated and the effect performed?