Ghost Reconciler is a side mission in South Park: The Fractured But Whole.
Plot details follow.
After unlocking the TimeFart Pause, Craig will call you up asking to meet him at Tweek Bros. Coffee. Go there to find him waiting outside. He asks you to give a note to Tweek.
Tweek does not respond how Craig would have liked. He asks you to bring Craig the receipt for their hamster, Stripe. Then, Craig tasks you with bringing him their hamster.
Go to Craig's House. Head upstairs to find Stripe in his room. Get him down onto the ground using Snap N Pops. Then, fart next to the vent he is in before quickly performing a TimeFart Pause. Then, simply go and pick up Stripe.
Return to Tweek Bros. Coffee to talk with Craig. Then, head inside. Tweek will trade you the laptop for the hamster. But before you can return to Craig, Tweek's dad intervenes. He takes the laptop and asks you to go to counseling with Tweek and Craig. Hand the counseling referrals to both Craig and Tweek to finish the mission. Talk to Mr. Tweak to receive your reward: The Electropunk Costume.