Fire grenade
This object looks harmless enough. In fact, the OP claimed that it was in his research lab for several years. It hadn’t exploded or anything, so maybe that’s why he and his fellow researchers didn’t feel the need to investigate any further. Instead, they left the investigation duties to the helpful minds at Reddit.
And Reddit delivered a response in record time. This object was not a lightbulb as its shape would indicate. Instead, it was actually a “fire grenade,” which is filled with water and chemicals to douse a fire. In the event of a fire, simply toss one of these grenades into the flames and pray that it actually works.