Full Tank Poppy, The Unkillable Yordle

This would be a pretty fun build. People would be unable to kill a poppy with so much life -- once you drop low, you pop face of the mountain. While your life is low, the shield would be huge. Poppy's passive would kick in and make that shield nearly unbreakable. Likewise with barrier.
Fun!
+ full damage, ult the support (Or best for the situation) and 1v5 pentakill because you explode anything you touch and they literally cannot stop you.