Nacatl War-Pride

This creature must be blocked by exactly one creature if able.
Whenever this creature attacks, create X tokens that are copies of it and that are tapped and attacking, where X is the number of creatures defending player controls. Exile the tokens at the beginning of the next end step.

The List

Future Sight

Nacatl War-Pride must be blocked by exactly one creature if able.
Whenever Nacatl War-Pride attacks, put X tokens into play tapped and attacking that are copies of Nacatl War-Pride, where X is the number of creatures defending player controls. Remove the tokens from the game at end of turn.

Salvat 2005

If Nacatl War-Pride becomes a copy of something else after the ability triggers but before it resolves, the tokens will enter as copies of whatever the ex-Nacatl War-Pride is now. If Nacatl War-Pride became a copy of something else and then left the battlefield, the tokens will enter as copies of whatever it was copying when it last existed on the battlefield.

If Nacatl War-Pride has left the battlefield by the time the triggered ability resolves, the tokens will still enter as copies of Nacatl War-Pride.

If it's impossible for Nacatl War-Pride to be blocked by exactly one creature, then the defending player may block it with multiple creatures or may leave it unblocked.

In a multiplayer game in which you're allowed to attack only one player each combat, the new creatures will be attacking the same player as Nacatl War-Pride. In a multiplayer game in which you may attack multiple players, you choose the player each new creature is attacking. It must be a player you're allowed to attack.

Putting an attacking creature onto the battlefield doesn't trigger "When this creature attacks" abilities. It also won't check attacking restrictions, costs, or requirements.