versed elk
It was my oppenent's turn during their Main Phase 1. I had Naturia Barkion face up on my field when my opponent activated Eradicator Epidemic Virus. They Tributed Lord of the Heavenly Prison from their field for cost. I was unable to chain Naturia Barkion effect to negate EEV despite me having 4 cards in my Graveyard available to banish for cost. I have a replay of the interaction available.
#Why was Naturia Barkion unable to activated its effect.
keen steeple
You should make sure you read all of your opponents cards