Glimmervoid Basin

The controller of a copy can't choose to pay any additional costs for the copy. However, effects based on any additional costs that were paid for the original spell are copied as though those same costs were paid for the copy too.

If an ability of a plane refers to "you," it's referring to whoever the plane's controller is at the time, not to the player that started the game with that plane card in their deck. Many abilities of plane cards affect all players, while many others affect only the planar controller, so read each ability carefully.

As a token is created by the chaos ability, it checks the printed values of the creature it's copying, as well as any copy effects that have been applied to it. It won't copy counters on the creature, nor will it copy other effects that have changed the creature's power, toughness, types, color, and so on.

If the spell that's copied is modal (that is, it says "Choose one —" or the like), the copy will have the same mode. Its controller can't choose a different one.

Anything that couldn't be targeted by the original spell (due to shroud, protection abilities, targeting restrictions, or any other reason) is just ignored by Glimmervoid Basin's first ability.

If a spell targets the same player or object multiple times, it won't cause Glimmervoid Basin's first ability to trigger.