I'm looking for a jigsaw death game type fic I read a while back. I've looked very thoroughly for it and am starting to doubt it's even on this site. Any help would be appreciated. Here's what I remember:

The fic was called something like 'the friendship experiment'. Starlight wanted to test whether or not the element bearers really embodied their respective friendship principles, and so puts them through 5 trials that would kill one participant each time, each themed around an element, so that five of the mane six would die, leaving one free to live with her guilt. There was some sort of magic forcefield so that no one could fight back.

The first test involved physical attacks with some sort of whip or branding iron, in which you could either take the punishment or pass it off to the pony next to you. Rarity always offloaded the punishment to the next pony and someone died of their injuries.

Later on there was a chamber with poisonous "laughing gas", in which Pinkie uncontrollably laughed herself to death.

Then there were three drowning chambers in which you could press a button to divert water from the other chambers into your own chamber; Twilight sacrificed herself to save the others and the remaining two, Rarity and someone else, went to the last trial:

It was based around honesty, and involved poisonous apple cider. It was formatted like a prisoner's dilemma, where you could choose to betray the other participant or not. They made their decisions, but the twist is that once you drank the cider, you could see at the bottom of the glass whether you had been betrayed or not; the other character Saw that Rarity had betrayed them.

Again, any help would be appreciated.

It's this
https://www.fimfiction.net/story/352115/the-friendship-test

This one is literally a saw pony version with a original trap, and solution
Chronicles of Jigsaw: Hello Trixie - Fimfiction

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Thanks!