Gangplank's kegs
I feel like they're going to be way too gimmicky. But I won't know until PBE comes back up for sure, the only way I could see them being truly helpful is if they deal extremely heavy damage and can be targeted with Parrley... No one is their right mind is going to get anywhere near them, it's like an uncloaked Teemo mushroom... If they turn out being shit, maybe they should cloak for a short duration after being placed? or maybe make them invisible to enemies for like five seconds upon placement.
If they end up being good, well I was wrong and am a dumbshit.