In my copy of Shantideva's Bodhicaryavatara, there is a footnote referencing a story about Shariputra losing bodhicitta. Apparently a demon asked for his right arm, Shariputra willing gave it. But the demon is offended that Shariputra offered it with his left hand, at which point Shariputra dispairs. According to the footnote, this story is told in the Lotus Sutra. But, I cannot find it there. (Granted, I do not have complete version of the sutra to search through available to me. So perhaps it's in the missing material.)
But I also have a vague memory of another story about a bodhisattva losing bodhicitta. The story, as I recall it, recounts how the bodhisattva works tirelessly to save all hell beings and at long last manages to liberate the last being from hell. Hell is empty. Having completed his work, the bodhisattva lets out a sigh of relief. And, in that instant, hell is completely repopulated once more. The bodhisattva grows despondent that his efforts have been to no avail.
I've tried a web search for this last one. While, not surprisingly, I get many hits on bodhicitta, I haven't found this particular story.
So, I have three closely related questions. Where in the Lotus Sutra does this particular story about Shariputra's loss of bodhicitta occur? And, who is the bodhisattva in this second story? In which sutra(s) can this story be found?