Wraith King + Tidehunter

Why this works

Putting these two heroes on the same team creates a simple but brutal problem for the enemy. Tidehunter forces a fight with Ravage, giving Wraith King a massive window to get on top of key targets and apply his stun. If the enemy somehow manages to burst Wraith King down, he gets a second life from Reincarnation. This extended chaos provides more than enough time for the rest of their team to clean up while the enemy is still dealing with his respawn. It's an attrition nightmare, forcing opponents to chew through two massive, durable frontliners.

Once Tidehunter gets his Blink Dagger, the pair can dictate the pace of the mid-game. He initiates and Wraith King follows, forcing the enemy into a lose-lose scenario. Trying to ignore Tidehunter lets him cause constant disruption with Anchor Smash, while focusing him leaves a free-hitting Wraith King untouched. Even a successful gank on one often fails, as the other is so durable they can stall long enough for backup. The opposition is forced to try and split them up or kite them endlessly, which is a tall order against a screen-wide stun.