pokemon card fighting Stone Energy | Vivid Voltage Item Rarity Fighting Gong | Mega Evolution

You can check out his write-up on the deck over on EDHREC

(From WOTC) Planechase, also known as Planar Magic, is an official game variant first populated by Planechase (2009) and basically acts as an augmentation to other formats though players can also play decks specifically geared towards this format

If Rottenmouth Viper leaves the battlefield before its triggered ability resolves, use the number of blight counters that were on it as it last existed on the battlefield to determine how many times each opponent must make the listed choice

Its controller may activate any loyalty abilities it now has as normal, but it notably cannot be attacked and it does not lose loyalty counters when it is dealt damage