Tusk + Viper

Why this works

Trying to survive a gank from this pair can feel awful. A Snowball rolls in, followed by a Viper Strike, and suddenly you can barely move. The problem is what comes next. Tusk wants to land a quick physical burst with Tag Team and get out, while Viper wants to stick on the target for a long time, letting his magical poisons do their work. Their damage types don't stack well and their ideal fight timings are completely different. They end up feeling like two solo-killers who happen to be hitting the same hero, rather than a coordinated pair.

This lack of real synergy means they often fail to secure the early kills they both need to get ahead. Any target with a defensive ability or a bit of magic resistance can often survive their combined assault. As the game goes on, Tusk and Viper become predictable. Enemies know the duo wants to isolate and pick off one hero, so they can counter it by simply staying grouped. Neither hero provides the area-of-effect damage or teamfight control needed to punish a five-man deathball, leaving their own team at a disadvantage.