I don't know what this is..

This grows in a bush, and it's all over my apartment complex... my kids keep grabbing them off the bush. are they poisonous?

 

Firethorn Pyracantha.

The berries are not poisonous but are very bitter so unpleasant to eat as they are. Boil them up with enough sugar and you can make jam from them.

 

so i shouldn't worry about my kids playing with them??

 

No worries about the berries (may not apply to berries on different plants, of course!). They might stab themselves with the thorns if they're not careful. But that's something kids have to learn about anyway.