Kalista's ''The black spear'' doesnt work?

Im not sure if this is a bug or something else but hey, i was playing kalista jungle just 4fun, problem here was i couldn't use my item ''The black spear'' on any of players from my team. When i tryed to use it, item would go on 10 sec cd and nothing would happend. Pls tell me if this is a bug or im completely wrong!