Invoker + Tidehunter

Why this works

Landing a big Ravage gives Invoker a perfect, guaranteed window to land his own area-of-effect spells. A well-placed Cataclysm or Meteor into Deafening Blast on top of Tidehunter's stun can be devastating for the enemy team. It turns Invoker's harder-to-land spells into reliable teamfight damage. Outside of that ultimate combo, a simple Gush can be enough of a slow to set up a Cold Snap or Sun Strike for pickoffs, giving the pair kill threat even when Ravage is on cooldown.

The game plan is simple: Tidehunter finds an initiation and creates space, while Invoker provides the follow-up damage from a safe distance. This plan is strongest in the mid-game, before enemy cores have Black King Bars. Once those BKBs come out, Invoker’s magic damage is much less effective, and the combo loses a lot of its impact. The duo has to secure a significant lead during that window, otherwise the enemy can often survive the initial stun and turn the fight around.