I like the Babylon 5 PPG hand weapon. Once shot at an assailant through a window, it left him plastered against the far wall under a layer of melted glass.
I don't remember the title, but in an early BW TV movie, two factions of aliens agreed to send 5 entity teams to Earth to duke it out. Winner gets to invade Earth. Perfectly disguised as humans (Think of the savings in makeup.) each was equipped with a pair of sunglasses that would disclose enemy team members and a small hand weapon that killed. That's all, no flash, no blast, no disintegration or wound, just aim and squeeze, the target dies. Kind of like the Paratime Police Sigma ray needler. (Think of the savings in special effects.)
Spoiler: Last surviving team member on one side falls in love with a human. She leads him on until she can pick up his weapon and zap him. Closing scene is an up angle through his fallen sunglasses. She is glimmering in the enemy telltale.