Phantom Assassin + Slardar

Why this works

Seeing Slardar's mark on an enemy makes things simple for Phantom Assassin. His Corrosive Haze strips away a lot of armor, making every one of her dagger throws and attacks hit harder. When she lands a critical strike on that specific target, the physical damage is amplified significantly. This allows them to try and burst down one key hero very quickly, turning a teamfight before it can get complicated. It's a straightforward combination of physical setup and physical payoff.

However, this plan is also very predictable. Opponents know that both heroes deal physical damage, so they'll often prioritize armor items or Ghost Scepters to counter the burst. The success of this duo depends heavily on Phantom Assassin and Slardar hitting the same target at the same time, which can be disrupted by good positioning or save abilities like a well-timed Glimmer Cape. If their initial target survives the focused attack, both heroes can find themselves overextended and vulnerable to a counter-attack.