How does madame lulu die in a series of unfortunate events?

Madame Lulu, the owner of the carnival, doesn't actually die in the "A Series of Unfortunate Events" books.

While the Baudelaire children encounter many tragic events, including the presumed death of their parents, Madame Lulu is still alive and well at the end of the series. She plays a crucial role in the final book, "The End", helping the children escape from the island and ultimately getting revenge on Count Olaf.

It's possible you might be thinking of another character from the books or the Netflix adaptation, but Madame Lulu survives the series.