An example of an "I accidentally a coca-cola bottle"-ism.

That’s probably my mistake rather than the original author of those words.

p.s. Firefox doesn’t think ‘grotesqueries’ is a word but dictionary.com does so I’ll let you off.

Firefox also thinks ‘Firefox’ isn’t a word.

Because there isn’t one. Implied pronouns are perfectly correct in many cases. In this case, “us” is understood to be at the end of the question. In fact, saying it would almost be redundant, since we already know you and your friend are the subject. What else would you mean?