Petey’s mobile phone is a roughly early-2000’s style flip phone with impressive battery life.
The only known incoming calls come from a blocked number that is later revealed to belong to Reghabi, although Petey consistently ignores the calls. Reghabi also appears to be the one who provided Petey with said phone.
Petey accidentally or on purpose leaves the phone behind in Mark’s basement and, upon finding it, Mark stashes the phone in a box of camping gear. The blocked number continues calling until Mark finally answers and ultimately meets Reghabi.