[Gameplay] [Twisted Treeline] Wooglet's Witchcap not Activating

While playing a game of Hexakill as Annie , I purchased a Wooglet's Witchcap . I seemed to be getting the stats from it, but when I got caught in a teamfight I would try to activate it, yet nothing would happen. I then tried it after respawning and still nothing. Anyone else have this issue?