Leaked memo from DARPA Shadow People Research Project. ( Shadow Bumpers -- fictional series )

One proven method to attract shadow people is Beta Delta brainwave alternating inducement pulses to the pre-frontal cortex. This is achieved with technology that can be easily acquired.  Kits can be bought on Amazon.

WARNING: Beta Delta brainwave alternating inducement pulses to the prefrontal cortex can cause temporary psychosis which can range from mild  to severe.  Some people can  become extremely violent. Do not operate  heavy machinery within 24 hours of the use of this technique.

Shadow people watching enthusiasts prefer to call Beta Delta brainwave alternating inducement pulsing as Bad Dreaming Attractor Technique or simply Bad Dreaming. The B and D representing Beta Delta respectively. The correct scientific terminology  of the technique is unwieldy.  Bad dreaming is also considered  a fitting description for the psychosis that commonly occurs when the using the technique.

Shadow people are hyper-dimensional beings  that cause  vibrations in the range of the visible electromagnetic spectrum of very dim colors.  That is why we perceive them as shadows. They also REACT to sympathetic resonant vibrations of the appropriate frequencies.  A shadow is proper description of their interaction with Euclidean space. They appear to be anthropomorphic  but we don't really know what they look like.  Aside from vibrations shadow people do not normally  interact with not exotic matter in any non-trivial way.

Though almost intangible in Euclidean space , DARPA is working on way to weaponize them.   There was an incident where 7 scientists were killed by shadow people. The scientists were experimenting with ELF ( extremely low frequency ) for a pentagon submarine communication experiment. It is theorized they inadvertently caused a harmonic resonance that not only attracted shadow people but made them hostile and caused massive and damaging interaction with our world.  All their work is said to be destroyed but many see what DARPA is doing as evidence that they are in possession of the late scientist's journals.

The deaths of the scientists prove that under some circumstances the shadow people can either directly or indirectly interact with matter in the dimensions accessible to humans in very  destructive ways.  

"If it is dangerous, we can weaponize it"  said Jim Spekter of DARPA Weapons Research.

Bad dreaming attractor techniques create hyper-rphasic super-harmonic resonance that attracts shadow  people . Meth psychosis causes the human brain to alternate between Beta Delta brainwaves just like bad dreaming attractor techniques. Bad dreaming is hardware and meth psychosis is the chemical equivalent.