[quote]Why did the precursors turn themselves into flood[/quote] This was actually an unintended outcome. While the Forerunners pursued their campaign of genocide against the Precursors, they sought out survival strategies - some Precursors went dormant and have yet to be accounted for, while others became a restorative powder that would revive their old forms. This powder was placed on ancient, automated ships which were adrift in space for over 10 million years. Time rendered the powder defective, so when the ancient humans and San'Shyuum started using the powder on the pheru (their domesticated pets) after a few centuries it ended up causing sterility, mass abortions, and creating strange furry growths that other afflicted pheru were compelled to eat. Humans and San'Shyuum were also psychologically affected by this and started to consume the growths on the pheru too, resulting in ritualistic behaviour where they'd force feed anybody who wasn't infected to eat the growths - and then they'd cannibalise the victim. This is what caused the first feral stage of the Flood across the human-San'Shyuum empire. It wasn't what the Precursors had intended to happen, but they saw the misery and pain that it caused and decided to roll with it. [quote]and i read somewhere that the ancient humans had a cure for the flood but hid it from the forerunners after they defeated the humans, is it true?[/quote] Yes and no. The ancient humans and San'Shyuum were convinced that they had developed a cure for the Flood and this was the reason why they'd managed to seemingly push the Flood out of the galaxy. However, the Timeless One reveals to the IsoDidact that this was actually a calculated move by the Flood in order to get the Forerunners to preserve humanity (as we know they were engaged in a war with humans for essentially glassing their worlds), there was no cure and the Flood purposefully retreated to infest satellite galaxies before returning 10,000 years later to take on the Forerunners. However, there is a good deal of evidence that points to there being [i]some[/i] kind of immunity to the Flood because there were humans who would come back from the Palace of Pain on Installation 07 (the lair of the Timeless One and Mendicant Bias) completely uninfected. This actually [i]confused[/i] the Timeless One, which is part of why it was experimenting on humans with the Flood.

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