Rith, the Awakener

Flying
Whenever Rith deals combat damage to a player, you may pay {2}{G}. If you do, choose a color, then create a 1/1 green Saproling creature token for each permanent of that color.

Dominaria Remastered

Flying
Whenever Rith, the Awakener deals combat damage to a player, you may pay {2}{G}. If you do, choose a color, then create a 1/1 green Saproling creature token for each permanent of that color.

The List

Duel Decks: Phyrexia vs. the Coalition

Flying
Whenever Rith, the Awakener deals combat damage to a player, you may pay {2}{G}. If you do, choose a color, then put a 1/1 green Saproling creature token onto the battlefield for each permanent of that color.

From the Vault: Dragons

Flying
Whenever Rith, the Awakener deals combat damage to a player, you may pay {2}{G}. If you do, choose a color. Put a 1/1 green Saproling creature token into play for each permanent of that color.

You choose whether to pay {2}{G} as Rith's ability resolves. Once you make that choice, no player may take actions until the Saprolings are created (if you paid) and the ability has finished resolving.