Deep-space artifact
From Halopedia, the Halo wiki
Summary
In the story of I Love Bees, the artifact is a cylinder roughly the size of a tire, with triangles, lines and dots running around the rim like a tire tread. It was discovered by the UNSC Apocalypso in late 2552, while on patrol deep in Covenant space.
The ship then headed back to Earth when Captain Greene feared that the Covenant had done something to their AI, Melissa. A crewman was influenced by Melissa to touch all the triangles, then all the lines, and then the dots, activating the artifect. The artifact sent out an enormous electromagetic pulse that blew the ship out of Slipspace, caused it to crash in Lunar orbit and shut down all communications in the Solar System for roughly seven seconds.
The artifact was taken to Chawla Base in Boston, MA for study. It was discovered to be sending out an oscillating pulse that grew steadily weaker; it was decided to be a countdown. So far, ONI thought it was a Covenant artifact but after the report from the Pillar of Autumn came, it was revealed to be Forerunner in origin.
A vigilante group led by Melissa broke into Chawla Base and turned off the artifact by touching the symbols in the reverse order. The artifact sent out another massive pulse, and turned off. Unfortunately, this attracted the Covenant's attention.
The artifact is likely 4orty 2wo's interpretation of The Ark.