What does the idiom "to catch a tartar" mean?

When harry discusses their approaching death, this could be considered: empathy theme morbid symbolism

Read the movie summary. two rival magicians compete for fame and success in edwardian london. when their bitter feud begins to escalate, they each resort to more and more dangerous tricks to try to outdo the other, ultimately placing the lives and sanity of those around them in jeopardy. based on this summary, the film is most likely a(n)

Don't eat the mushroom its poisonous