Marker is the thirtieth story arc in EGS:NP. It started with EGS:NP Comic for 2016-06-25 and ended with EGS:NP Comic for 2016-09-05. It's canon and it features Pandora Raven playing with mortals. It's happening in late October, during the timeskip.
Pandora went to the mall and tried to find people to mark who would have desire for hard-to-hide spells, especially transformation ones, hoping that Halloween being near will raise her chance. To help the associations even more, she pretended to be a college student with a psychology assignment and asked what would people like to be for one day.
She wasn't so lucky - at least not on-panel. She marked good Tom (yes, that power to sense if puppies are in danger is actual spell), found several people with "biological primary directive"-related desires she possibly didn't marked, Rich and Larry who creeped her so she didn't marked them, Ashley who was too good to be markable with transformation (her desire is to transform OTHERS, and she sees it as bad thing to do) and markable desire for minor health spells she ignored ... and Liz who she DID marked with someone but we don't know what.
Then she found Rhoda and Catalina. Rhoda is of course already marked, and Pandora spends some time complaining how she hates name-based affinities like the one Catalina has ... but then decided to mark her anyway.
Then she was surprised by (presumably) Catalina ... but what happened is topic of NEXT storyline.