A derivative or follow up work adds mecha this time.
Thinking of a better name, such as "Like This Show, But With Mecha", or something else. There was an old TRS thread, that brought up splitting this off from Instant Awesome, Just Add Mecha, and this is just following that up. Its Sister Tropes can be split as well if they have enough examples. Rolling Updates.
You can't fit even one giant robot in a Victorian boarding house (A Little Princess), but you can fit plenty in an interstellar war (Soukou No Strain).This is whenever a work isn't about Humongous Mecha, but a work that redoes the premise (usually a Spinoff, Spiritual Successor, or Follow the Leader), is largely about them. Say there is an old fairytale about a good spirit that has to stop a horde of The Fair Folk from invading a village. Then someone makes an adaptation where the fair folk are aliens the pilot giant robots, and the good spirit turns out to be the only one who can pilot the Super Prototype and save Earth. A Sub-Trope of Instant Awesome, Just Add Mecha (since the source work wasn't about mecha, and the new work throws it in), Recycled IN SPACE!.