… For example, in Fantasy Fluxx, the Dungeon says “You can discard this card if you discard the Trove of Treasure… from play”. The Trove of Treasure on the other hand says “During your turn, you may discard this to steal a Keeper”. Can I discard the Trove, steal a Keeper and get rid of the Dungeon at the same time?

A: Each benefit has it’s own cost, so: no, you can’t get multiple benefits from one cost.

In Star Trek: DS9 Fluxx, the Gold-Pressed Latinum works exactly the same way as the Treasure, and there are several Fluxxen which have more than one Creepers where you can get rid of it if you discard a Keeper – and it has to be a separate Keeper for each Creeper you want to get rid of. In DS9, the Jem’Hadar and the Founders; in Voyager Fluxx Species 8472 and the Krenim Timeship. In the upgrade pack for Firefly Fluxx, Hands of Blue, and Reavers.

The Jabberwock in Wonderland Fluxx also works this way, but it’s the only Creeper – but you can’t discard the Important Message for its benefit and use it to get rid of the Jabberwock.

See also: When a Keeper/Creeper (or Rule) says I can do something if I discard or move something, can I do that as a Free Action or…
And also: If a Creeper says I can get rid of it if I “discard a Keeper.” Does this mean voluntary discard…
And also: If I have a Keeper which says I get some benefit from discarding or moving it…