A "live grenade" refers to a dangerous explosive device that is activated or "live," meaning it could explode if handled improperly or triggered accidentally. Full definition
Some other nice touches include a voiced intro cinematic, and the way many stages are slightly tilted, forcing players to account for the way items like live grenades will roll or bounce. (bitcultures.com)
(He tries to entertain Stalin with a ridiculous story about how they used to play hot potato with live grenades back in winter in Stalingrad, just to keep their hands warm.) (metroactive.com)
The members of the inner circle drink, eat, and drink some more in Stalin's grand mansion, regaling each other with stories of the war (in Khrushchev's case, telling how he threw live grenades at POWs to watch them dance) and passive aggressively mocking each other for their capital - C Comrade's amusement. (markreviewsmovies.com)