Susie

Susie is Stephen Patrick's sniper rifle, first seen in the video '04/30/11'. According to Stephen after becoming Mr. Collector, he sleeps with Susie with him in his bed at night. Mr. Collector abandoned Susie in the bushes behind a church and is not known to have ever gone back for it.
The Susie owned by the Stephen of the APCollection universe is likely still at his house, unless Mr. Collector had taken it during his time there.