In my story, the main character is swept into a secret society that protects this really important secret. They call the secret the orb, and it's supposed to be really frickin powerful, but I need some horrifying abilities that the orb has so taking ideas
Omniscience
sucking the life force out of those near it
Why don't you give it the power to do, nothing.
Like, have everyone freak out about it and struggle to keep this orb a secret, and have hundred of villains or even regular people come after it and have to kill every one person, only to find it it's just as its name suggests.
An orb.
Give it the power to destroy humanity itself by tricking people into thinking that it has any powers at all.
that's honestly really scary
snuffing out the senses of people near it so they feel like they're dying
Playing off of @"Teenage Angst"'s idea, the orb could be a physical representation of human flaw. It, at its core, is total lawlessness and anarchy. Humans try so hard to fit into the mold of "morality," but at our core, we're just animals, which is what it brings out in us. It has the power to bring down nations and empires from the inside. This, however, begs the question: why do people keep it around? Is it indestructible, or did the founder of the secret society have some "less than pure" intentions? Could the goal of the main character be to destroy it?