 SCP-577 is an animated, levitating mass of ammunition of various calibers. Approximately 40% of the ammunition is 9mm. However, large quantities of 10mm and .45 ACP rounds have also been noted. Bullets within SCP-577 are capable of leaving the mass and firing at speeds comparable to those from a standard handgun. Occasionally, the mass has been observed forming recognizable shapes and likenesses, commonly those of domestic animals. SCP-577's total mass rises consistently, with approximately 1000 new pieces of ammunition appearing in the mass each year.