the best way to counter it is avoiding her ganks, because she always ganks while in disguise which hide her ult for a moment making it more dangerous and hard to avoid. But avoiding her ganks is hard right now since she is invisible on the minimap while disguise as small wolf, small raptors or small golen. So the only way to avoid the ganks is by warding really hard and looking at the map constantly (don't trust the minimap)
But considering that it's kinda like Nunu's ultimate you can just try running away I guess?
galio's ultimate is good enough to counter neeko's ultimate.