After hooking a Survivor, Pop Goes the Weasel activates for the next 35/40/45 seconds:

Performing the Damage Generator Action on a Generator instantly regresses it by -20 percent of its current Progression, after which normal Regression applies.

Your Terror Radius is increased by 26percent.  Gain 100percent more Bloodpoints for action in the Deviousness category.

Fresh blood marks are considerably more discernible than normal and can be tracked for 4 seconds longer than normal.

As soon as an exit gate is opened, Blood Warden is activated.  The auras of any Survivors located within Exit areas are revealed to you.  Once per match, hooking a Survivor while Blood Warden is active calls upon The Entity to block both Exits for all Survivors for 60 seconds.

You reduce the duration of pallet stuns by 50percent.  Has no effect while carrying a Survivor.

You become obsessed with one Survivor.  When the Obsession loses a health state, your Terror Radius transfers to the Obsession for 30 seconds, and its radius is set to 32 meters.

You are granted the Undetectable status effect for the duration.

The Survivor with the transferred Terror Radius is also considered to be "inside the Terror Radius" for other purposes.

The Killer can only be obsessed with one Survivor at a time.  Undetectable hides the Killers aura, Terror Radius, and Red Stain.