Stun bomb
A stun bomb was a hand-thrown weapon. It was utilized by Romulans in the 24th century. Designed with a time-delay setting, stun bombs were capable of attaching to an enemy and incapacitating them without causing permanent physical damage, in much the same way as a phaser set to stun. Romulan stun bombs produced green electrical arcs when activated.
In 2384, when a Tal Shiar strike team boarded the USS Protostar intending to steal it, they used stun bombs to neutralize Jankom Pog and Zero, who were on the ship at the time. (PRO: "Masquerade")