When millions of people opened the game Brain King inside WeChat to get their daily quiz fix recently, it was gone -- replaced by a message saying it had "violated regulations.” Later, the game's developers apologized for failing to review quiz questions that were “misleading and seriously wrong.”

It’s a stunning turnaround for a game that was quickly gaining mass popularity. Brain King was a mini program within WeChat, meaning it was playable from inside China’s ubiquitous app. Playing with your WeChat contacts or pitted against a stranger, whoever answered a series of questions fastest won.

It could be the source of those questions that are to blame for the game's removal -- many of them come from users. Chinese netizens are pointing to questions related to former president Jiang Zemin as the reason for Brain King’s troubles, but it's still unclear exactly what triggered its downfall.

Caption: Chinese netizens speculate that questions about Jiang Zemin may be to blame.

Users have complained about Brain King’s crowdsourced questions before -- not for controversial content, but because they are tired of seeing absurd questions, or ones which are impossible to answer correctly.

Examples of the more ridiculous questions reviewers posted online include:

Q: Are you dead?

  • I’m healthy
  • No
  • Dead
  • Not healthy

*The "correct" answer is "Dead"

Q: Which year did World War I happen?

  • 1999
  • 1008
  • 2001
  • I don’t know but I’m honest

*World War I began in 1914, an answer not listed in the multiple choice options.

In one report, the company behind Brain King said that user-generated questions pass through a software filter first, before they’re rated by fellow users and checked by the company’s own in-house reviewers. It claimed it had struggled because there were simply too many questions to handle.

In its apology, Brain King says it will stop sourcing questions from users and work with authorities and experts to review its content.