Well, normally we'd treat "wielki" as something bigger than 'big'... but here it does make sense indeed I guess. Added now.

Didn't you know? Everybody in Poland has a big gray elephant in their household ;)

But seriously, did you use the option to "strengthen your skills"? If so, they're sometimes throwing one different sentence which isn't from the topic you're working on into the practice to mix it up, it seems.