It's a leash...

Dread coiled tightly in her chest, and a chill ran down her spine as she continued to read.

I am aware of your involvement with the eco-terrorist organization known as Avalanche, as well as the identities of its members, their schemes, and the locations of their bases scattered throughout Midgar. I believe it is time for us to have a chat. Come immediately.

The news was devastating. Shinra wouldn't hesitate to execute all of them...

Except, why weren't they here now? And what was the purpose of the collar around her throat? And where was she supposed to go? The letter didn't contain an address or direction. She turned it over to find an apparent inventory of the package she'd received.

~1x Leash materia (prototype)

Tifa's mind reeled as she absorbed the additional information. She was an old hand with materia, but had never seen a pink one before. The implications of the name sent a chill down her spine, and she couldn't help but wonder at its senders twisted sense of humor. Tifa yelped as he note, laced with dust from ground fire materia, burst into flames, destroying the evidence.

Before she could react further, the materia lived up to its namesake. A sudden tugged at the choker around her neck. Startled, she stumbled forward, caught off guard by the unexpected pull. Panic surged through her veins as she realized that the Leash materia was exerting its control over her.

Refusing to succumb to Shinra's machinations, Tifa planted her feet firmly on the ground, digging her heels in with stubborn determination. With a defiant glare, she braced herself against the invisible pulling her forward, every muscle in her body tensed with resistance.

Despite Tifa's valiant struggles, she found herself inexorably drawn forward, inch by agonizing inch. The choker tightened around her neck, her, its grip unyielding as it compelled her to obey its commands.

The buxom warrior thrashed beautifully against the Leash materia, her pride as a warrior fueling her defiance. But its influence was relentless, its hold unbreakable as it dragged her inexorably toward the door of 7th Heaven.

Desperation surged within her as she realized the futility of her resistance. But still, she gripped the door frame, not to ripped out of the safe space of her bar. The materia tightened, gradually cutting off her air supply until her hands flew to her throat. It unclenched and dragged it's gasping occupant outside, red faced and helpless.