Creature â Snake
Myriad (Whenever this creature attacks, for each opponent other than defending player, you may create a token that's a copy of this creature that's tapped and attacking that player or a planeswalker they control. Exile the tokens at end of combat.)
Whenever Broodbirth Viper deals combat damage to a player, you may draw a card.
You choose whether each token is attacking the player or a planeswalker they control as the token is created.
The token creatures all enter the battlefield at the same time.
The term â€œdefending playerâ€ in the myriad rules (or any other ability of an attacking creature) refers to the player the creature with myriad was attacking at the time it became an attacking creature this combat, or the controller of the planeswalker the creature was attacking at the time it became an attacking creature this combat.
If the defending player is your only opponent, no tokens are put onto the battlefield.
If myriad creates more than one token for any given player (due to an effect such as the one Doubling Season creates), you may choose separately for each token whether itâ€™s attacking the player or a planeswalker they control.
Each token copies exactly what was printed on the original creature and nothing else. It doesnâ€™t copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and Equipment attached to it, or any non-copy effects that have changed its power, toughness, types, color, and so on.
Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any â€œas [this permanent] enters the battlefieldâ€ or â€œ[this permanent] enters the battlefield withâ€ abilities of the copied creature will also work.
Although the tokens enter the battlefield attacking, they were never declared as attackers. Abilities that trigger whenever a creature attacks wonâ€™t trigger, including the myriad ability of the tokens. If there any costs to have a creature attack, those costs wonâ€™t apply to the tokens.