One nasty build... But the dev is even nastier for not nerfing this build. There's a certain patch in dota for Medusa becoming invincible, Medusa passive is she have mana shield, it means her mana are used as hp while also reducing the damage she received, and theres an item where u gain mana by receiving damage while also reducing the damage taken. So, when u burst her with all ur teammates, all u did was healing her. She literally becomes immortal during that patch. Less than 24hrs that meta got nerfed to the ground.
How to counter this? There's a hero who burns mana faster than reducing ones health, theres also a hero who execute anyone below the threshold hp, and since Medusa hp is lower than anyone since shes using mana as her hp, u can literally just press R on her and kill her instantly when u hit lvl 6.