Trope-a-Day: Spare Body Parts
Spare Body Parts: The poster-people for this are the kaeth, who come from the kind of… robust ecology (see: Had to be Sharp) that makes a selection of extra backup organs very useful indeed. And a special shout-out goes to the myneni, who have a kind of this by default by virtue of forming all their organs ad hoc anyway.
Of course, it’s not like a lot of other species haven’t been merrily engineering redundancy into at least some clades of themselves in the name of extra resilience, starting with auxiliary hearts and working down, even if they can’t do the same sort of holistically comprehensive job…