I arrived home after a four hour drive and heard some crazy rattling while the engine was idling. You can see the front of the pulley hanging there, source of the noise. The missing ribbed section of the pulley is presumably in pieces, none of which are laying around on the undertray. Seems like the remaining back half of the pulley was driving the belt okay, for an unknown length of time. The belt seems to be in normal condition.
Does this look like the OEM pulley? I bought the car from an offroad dealer and don't know if it is overdriven and/or tuned. It does have the NeedsWings *single* CAI.​​​