I learned this from an iG game earlier. Faith and YYF with Dark Seer and Bounty Hunter combo. Dark Seer cast Ion shell on BH and invi to go harass the enemy without knowing their HP decreasing. If cast on Ion shell on creep, creep will die faster but if cast it on BH/Riki/Clinkz, I think it would be a great early game combo. Maybe can be used on Lycans wolves if Lycan max out the wolves first so they can invi.