The decoy grenade is equipment featured in Counter-Strike: Global Offensive. When thrown, it emits the sound of the user's most powerful weapon, giving an illusion that an enemy nearby is firing. After a certain period of time, the decoy grenade will self-detonate.
Once enemies become aware that a decoy grenade has been thrown, they will focus their attention on previous or new objectives
Furthermore, if the opposing force is able to communciate effectively and frequently, they can alert each other if they discover an active decoy grenade thus rendering it completely useless afterwards.
Noisy (not recommended to use when the enemy is occupied elsewhere and if you do not want to be seen)
The grenade must be thrown correctly otherwise, the enemy force may actually arrive to your position!