Monster of the Day: The Production and Decay of Strange Particles

Source:  The Outer Limits
Location:  Another dimension, and nuclear research facility
Threat Assessment:  6.  The energy needs a shell to exist, so it flows into people wearing suits that were suppose to be proof against radiation.  They are intelligent, and don't feel pain.  If you destroy a suit you don't destroy the energy.
Limitations:  They can't operate far from their dimensional rift.  So it's best to close that sucker off.
Personal Note:  For some reason these scared me as a child.