I hope that you are reading this for purely comedic purposes. I hope that you haven't found yourself in yet another situation where my expertise in surviving the extreme going to be of some use to you but if you are reading this for your own survival my prayers are with you and I'll skip the morality tale until the end of this guide because you need to know the basis of how to survive a gargantuan. I'm going to start by defining gargantuan and then their most common types.
The gargantuan are Earth's way of punishing us for mistreating the planet that we live on. They are usually born of toxic sludge or nuclear radiation. This information is only of minor use, it might tell you how the creature was made and in certain cases how to defeat the monster though I highly recommend that you simply run for the duration of the attack and then ready yourself to rebuild afterwards. Only in the most extreme of cases should the monster be confronted. In fact right now we should review the first rule of surviving a gargantuan. I want you to say this part out loud.
Run, run or I'll be well done.
That's very important, particularly for the kinds that are capable of breathing any kind of fire or radiation. You'd be amazed how common it is that these giant monsters that can knock over buildings without trying and could easily kill us without being able to set the world on fire can in fact set the world on fire. I know it's not really fair but that's just the way that these things work. So if it can breathe fire/sludge/electricity/radiation you should get the fuck out as fast as possible.
Okay now we should take a moment to identify the monster. What are its origins? Is it a toxic monster that might be attracted to waste dumps? Is it born of nuclear radiation where it will be drawn to your power plants? Is it made of trash so you should get as far away from dumps or was it a military experiment? If you know what the creature's home or goals are you should make certain that you are not at the goal or equally important between the monster and its goal.
Is the monster intelligent, usually this boils down to if it looks like it's a giant mammal or a giant. . .well anything else. You can't reason with a giant lizard, it doesn't care what your name is or why you should be allowed to live. Giant insects have been known to respond well to singing midget women, if you can't supply any of these I suspect that a full collection of Bratz dolls and a recording of the Spice Girls "Tell me what you want" may suffice to sooth the beasts. Giant mammals, most often apes, are a bit of a problem. They can often reason out any traps that you've set for them and worse than that they will actively hunt down their goal, most often the sexiest blonde around. Normally I would say that you should fight for Nicole Kidman with all your might, but seriously King Kong will knock you straight the fuck out and there is no real point in you dying.