if he surprise you, you can react with little micro by destroying wagons(bm pwnd it all ) wave from tc if you have him, or kill necros just by esnare focus .. you dont need air, if you have a lot of ground, katas should do they work too, .. or if he had too many of it, you can easy esnare&focus hero, when he have tp, he will tp out and you got time ... if he is doing this necro/wagon strategy, it mean that he is camping in his base, so you got all the map for yourself, you can make also expo and lvl up heroes+items ....