What can we zerg do when we sense the terrans are massing tanks and marines? Especially when they are all bunched up, any ground units will die under siege fire, mutalisk will be slaughtered when flying over the marines.
I was thinking maybe Roach with all of its upgrades but it doesn't seem viable as it costs quite a lot.
Lot's of roaches with burrow and underground movement. First unburrow a couple of roaches in the middle of the marines to decimate them then unburrow under the tanks so they take themselves out. You could also use burrowed infestors that can spew infested marines while burrowed.
It's not viable, but people will tell you to stop being bad and do that anyway, because idiots who don't play Z don't understand how costly and how long it actually takes (even if you're "rushing" to it) for Z to get a decent maount of Roaches up with burrow, with upgraded speed, and with the ability to move while burrowed.
"burrowed Roaches" is all anyone can ever come up with when people ask how to counter tanks as if that will A. always work even though a T can just *GASP* scan and B. You can do it in a quick amount of time.
Honestly you need speedlings (that's actually reasonable possible before they have too too many tanks, but again they can fall easy to the marines as well unless you have enough) combined with Roaches and I suppose you could try to get some Banelings. Then you have to micro properly or it will all get obliterated and find a way to sneak Banes up to the marines.
It's just funny when people suggest only burrowed Roaches. That's hardly even doable quickly on one base, not to mention a good T can have a Thor out or coming by then anyway, then you're really in trouble because now mutas will have problems too.