If robots or our own stupidity doesn't get us first, then it's definitely going to be those deep sea creatures. We've already seen monster lobsters, and it stands to reason that our fishy frenemies also have tinier foot soldiers, ready to form the advance attack army. Or in this case, pincer soldiers. Because if you're going to launch a terrestrial invasion, you can't do much better than a swarm of crabs.
Think we're joking? This picture tells a different story. This crustacean invasion actually happened, and although there were no human casualties, that doesn't mean the second wave won't take off a few toes. And you know that once they get our big toes, we're just going to topple and fall like fleshy dominos. You've gotta hand it to them - their plan is flawless.