[Belker]

I was digging around for some Baltimore folklore for a current project and came across the following snippet about "The Phantom of O'Donnell Heights". I'm thinking of having it make a re-appearance for a run, and while my first thought is that it's a spirit, is there some sort of paracritter that might work better?

The Phantom of O'Donnell Heights
The Phantom of O'Donnell Heights is a reported phantom or monster that for roughly three weeks in 1951 plagued the east Baltimore community of O'Donnell Heights. The reported phantom was remarkably similar to sightings of Spring Heeled Jack.

Appearance: The phantom appeared as a tall man clad completely in black and wearing a black hat and black cape.

Lore: For roughly a three-week period starting in July, 1951, reports of the phantom were made by frightened residents. Residents claimed they saw the phantom leap out at them late at night and swore they heard him running on their rooftops. Some girls even complained the phantom hid under cars and beckoned them, saying "Come closer, my dear.". The phantom was even blamed for the break-in of an elderly woman's home. Consistent in most of the sightings were the leaping abilities of the phantom and the fact that the phantom seemed to disappear into local cemeteries. One older resident claimed she heard organ music coming from the cemetery chapel at around 1:00 AM one morning. Residents began arming themselves and began to patrol the streets at night. Several more sightings of the phantom were made by the patrollers, unfortunately the phantom always eluded them. The police investigated several sightings and found that witnesses had mistaken a pipe on the roof of a building as well as an angry German shepherd dog for the phantom. The police also did not locate the phantom, but did manage to locate several teenagers who were up to usual mischief. In the very last sighting of the phantom in August, the patrollers swore they chased the creature to the cemetery and witnessed it jump into a sarcophagus and disappear. The phantom was sighted no more.

Powers: The phantom of O'Donnell Heights displayed supernatural strength and the ability to make inhumanly large leaps and bounds, large enough to leap over six-foot tall fences and similar barriers, as well as be able to jump from rooftop to rooftop.

Original link here: http://thedemoniacal.blogspot.com/2010/04/phantom-of-odonnell-heights.html

[Mantis]

Go with one of the shadow spirit types from Street Magic, most likely a Nightmare spirit. This is assuming you want this thing to be more than something that just gives people a fright by going 'Boo!'.
Another option might be to use something like a Blackberry Cat with illusion powers and have it guarding a lair or something. Maybe just having fun. Either way it makes the characters and it's victims think it is much worse than it is.