Plot Devices

Can someone tell me what's the difference between MacGuffin, Plot Device and Magnetic Plot Device? I find it difficult to elucidate what items drive the plot, what items are interchangeable or what items do something.

A MacGuffin is a Plot Device (meaning a subtrope) that serves as a motivation for the story, but is ultimately irrelevant as to what it is exactly. If you can't just switch it out for a different MacGuffin, it's probably a different kind of Plot Device.

A Magnetic Plot Device is just any kind of Plot Device (also a subtrope, and can overlap with MacGuffin) that for one reason or another draws interesting plot elements (a.k.a. weirdness) to the protagonist or her area.

So... A story has a meteorite fragment that gives powers to its owner. One Big Bad has it and another comes up with a plan to steal it. What would that be?

Green Rocks.

Doesn't it count as something else besides Green Rocks?

Generally one wants to use the most specific applicable trope instead of fishing around for everything that could possibly apply. MacGuffin is a specific subtrope of Plot Device used when the device in question is sought after but could be reasonably replaced with anything. A gold idol stolen from a tomb would be such a thing: it could be anything — a diamond, a vase, a satchel of money — the point is that people want it, not what it inherently is.

A space meteorite that grants people superpowers is not a MacGuffin because it has a specific effect on the plot derived from what it is and does.

Speaking of, does Applied Phlebotinum fit as a subtrope to Plot Device, or is it a wider concept?

I'm not sure if it would reasonably be considered a subtrope, since Applied Phlebotinum can apply to setting as much as to plot.

edited 17th Aug '16 10:58:43 AM by Fighteer

Yeah, that's what I was unsure about. Although, I didn't really find a way for it to apply to a setting specifically while looking through it, but there are some concepts I maybe wouldn't count as Plot Devices. And if Applied Phlebotinum also applies to explanations, like Techno Babble, it's not always a Plot Device.

Let's take an example: Star Trek. The starships in that franchise all run on hefty doses of phlebotinum, but in not all episodes does that phlebotinum matter to the plot.

Now, it's worth noting that the description for Applied Phlebotinum is a bit narrower than I'm implying it to be: the applied part specifically means that someone is taking the phlebotinum and using it to do something needed to resolve the plot. So in that context it would definitely fall into the category of a Plot Device. I just worry that it's being misused a lot.

edited 17th Aug '16 11:01:38 AM by Fighteer

So by "applying to the setting" you basically mean what amounts to a plot device that doesn't actually affect the plot, just the background setting?

edited 17th Aug '16 11:05:48 AM by AnotherDuck

Yes. The warp drives in Star Trek are setting; they explain how ships get from one place to another but normally they have no direct impact on the plot. In some episodes, however, they get disabled or the characters have to Reverse the Polarity on them or they start Going Critical or whatever, and then they do matter.

An example of Applied Phlebotinum might be: "The Monster of the Week is immune to our phasers. If we Reverse the Polarity on the warp drive, we can disable its immunity!" They're taking the phlebotinum — the warp drive — and applying it to solve the problem, in a way that is essentially arbitrary.

edited 17th Aug '16 11:19:48 AM by Fighteer

I think "applied" in AP can also be applied to the world settings. See: Narrative Filligree and Worldbuilding.

There's a reason AP is also called "Handwavium".

By the strict definition of the trope, the applied part of Applied Phlebotinum specifically distinguishes its use to advance the plot, as opposed to the more general use of phlebotinum in a work's setting. Of course, it's further confused by the original meaning of phlebotinum as "a magical substance or technology whose properties are defined by the requirements of the plot as opposed to science or logic", implicitly marking phlebotinum as a Plot Device.

edited 18th Aug '16 7:12:07 AM by Fighteer