So i am Gamemaster of an RPG, the location where the Party is, for the last few months, is a dyson Sphere. 

Now i would like to let them go anoter place. So i need to destroy it on the best possible Way: I thought some nice Metorids. 

So my Question is: How many Metroids do i need to shoot, **and how big do they need to be**, to Effectivly destroy **all the hability** of a Dyson Spehere? How would the Scrap of the Sphere react if the struckture is out of balance? Would the whole stuff just wobble around like waves on a Watersurface? Also - how could i explain somthing like that, so it sounds possible. 

"A big meteorid just appeard on the screen" - seems to be to easy for a civilisation that made an Struckture that is bigger than a Sun. 

I would like to let them screen the scrap pieces in a later advanture but not if that sounds to artificial. 

To The Sphere:
From the sun to the outer layers 


 1. Habitable Zone: citys, agra farms, places
 2. Support Zone: Electrics, water supply first Struckture level
 3. Main Struckture: the other Struckture levels where everything is build on.
 4. Spaceports and Cargo System: An infrastructure on the outdside where Spaceships can be dock and a network of "Trains" transport Cargo
 5. Shield pylones: For shielding the whole Thing against little Meteorids and Ships. 

I described the hull of the Sphere about 200 - 500 meters thick (according on what place of the sphere the Players were). 

EDIT: The Core of the Question is "what could possibly destroy a Dyson Sphere" not "how should i Destroy it"