I doubt EMP would work.... the only way people on earth would outwit these 'foreign beings' would be by having help from one of them. meaning, yes one alien helps us take the rest down if aliens are evil.
I'm going mad :S
Sometimes, i don't like to have a mindset like this because it makes me forget about religion.
Personally, I think we're part alien species because evolution wouldn't give us a huge growth spurt and whatnot unless aliens helped us at one point, if that's not the case, I think that these aliens constructed us with their technology, that they have a cellular technology while we're still with electronics... The body's of earthly life forms are organized, not symmetrical but organized. the earth doesn't grow organized, does it? -- The alien species that 'created us and animals and plants' may be 100000x bigger than us because our planet is small compared to others if you haven't forgotten that, there are many other galaxies, many other dimensions I suppose. So if they made us, plants, and animals they must've done it when their species has been alive for quite long.