My husband and I booked a hotel room for our vacation. In the room, I discovered this. I’ve been staring at it for half an hour, but I still can’t figure out what it is. Does anyone know what it is? The answer is in the first comment. 

That strange object dangling from the top corner of the door trim is a spider egg sac—specifically, the distinctive egg sac constructed by a Brown Widow spider (Latrodectus geometricus).

While common house spiders create smooth, round, cottony spheres, the brown widow builds a highly recognizable capsule that looks like a tiny, spiked khaki ball or a marine mine.

Anatomical Breakdown of the Discovery

• The Spikes: The geometric tufts or spikes protruding from the surface are actually specialized silk knobs. Arachnologists believe these structures serve an evolutionary purpose, acting as a defense mechanism to make it difficult for parasitic wasps to pierce the outer shell and lay eggs inside the sac.
• The Silk Tether: The thick, fibrous cord extending upward anchors the capsule firmly to the wooden moulding. Widow spiders utilize an incredibly strong, high-tensile structural silk to ensure the sac remains suspended and safe from crawling floor predators.
• The Internal Volume: Inside that single, small capsule—which measures only about 10 to 12 millimeters in diameter—the female spider can pack anywhere from 100 to 150 individual eggs.

Understanding the Species

The brown widow is a cousin to the more infamous black widow. They favor dark, sheltered, undisturbed micro-habitats, making hotel door frames, curtain pleats, closet corners, and the undersides of outdoor patio furniture prime real estate.

Is It Dangerous?

While all widow spiders possess neurotoxic venom, the brown widow is generally considered far less hazardous to humans than the black widow.

• The Bite Reality: They are exceptionally timid and typically run away or drop to the ground and play dead when disturbed.
• Venom Delivery: If a female is squeezed or forced to bite to defend her sac, the bite is highly localized. They inject significantly less venom than their black counterparts, usually resulting in temporary redness and localized pain rather than a severe systemic reaction.

What You Should Do Next

Since you are staying in a commercial hotel room, you do not want to risk crushing it or poking it yourself, as it could be close to hatching and release dozens of tiny spiderlings into your living space.

1. Leave it undisturbed: Avoid swinging the door violently or touching the tether.
2. Notify hotel staff: Call the front desk and let them know there is a pest control detail needed on the door moulding. The housekeeping or maintenance team can easily remove it safely using a vacuum hose attachment or a damp cloth with isopropyl alcohol to neutralize the area.