Sundial of the Infinite has an activated ability that you can only play on your turn, and when the ability resolves your turn will end. It may seem like it is a negative effect, as it can be hard to understand why you would want to end your turn prematurely. However there are often things in your own turn that are not that great for you, and the Sundial will allow you to bypass them. It does this because when you end a turn with the Sundial all spells and abilities that are on the stack will be removed from the stack and exiled.

One of the more effective things to do is to avoid triggered abilities with negative results. An obvious negative trigger would be one of the delayed triggered abilities created by the Pacts from Future Sight, such as Pact of Negation. The best way to effectively counter a delayed trigger in this way is to make sure it is on the stack. Crumbling Colossus has a delayed triggered ability that is created when it attacks and it goes on the stack at the next end of combat step. If the turn is ended in combat but before this trigger can go on the stack then it will wait around until the next end of combat step. This means that unless you time things right you wil end up sacrificing your Colossus in your opponent’s end of combat step.