This isn't something you see every day. Via YouTube user, PrincessHira:
During a local club match in Isfahan, Iran some spectators threw a hand grenade on field,a player found it and thought it was some other object and threw it on sidelines just in time, if he had done this a few seconds later his hand would have been blasted. The game was called off and police have started investigating this case.
Blasting it into the net seems to be the least of this matches' worries. Scary, ridiculously insane, and overall just one of those holy sh*t moments that makes you glad you're not at a soccer match in Iran. VERY fortunate that everyone ended up alright.