This is a difficult one to get, but if you go into the Japanese work place, you may have your boss say this (a common phrase popular amongst Japanese in their 50’s and 60’s).
ウルトラC (from “ウルトラ”, Wikipedia)
So the term originates back from the 1964 Tokyo Olympics. Gymnastics at the time seemed to be the popular competition amongst the Japanese, and everyone would anticipate the “C level” move by the Athelete. Techniques were judged on a scale of ABC, (A being the easiest and C being the most intricate), and viewers would want to see the “Ultra C”, meaning something that even overly succeeds the “C” rating.
In modern days, it would be used as something meaning “the unexpected”, “the Big Bang” etc… more specifically used in the workplace, for seniors to point out “special moves” or just simply “great outcome and results” from the younger employees.
Examples would be
上司（Boss)「山田君、最近なんかコン詰めちゃって〜 忙しいのか、おとなしいのかわからないよ〜 どうかしちゃったの？」(Yanada-Kim, either you’re hands are really tied up or you’re just really quiet now a days… what’s up with you?
山田くん(Yamada)「いや〜、ただ単に要領が悪いだけっすよ〜！」(oh nothing really, sir. I’m just an plain inefficient, imbecilic guy *note: this is just being “plain” humble)
上司「そうか〜、なんて言っちゃって。どっかのタイミングで山田くんのウルトラCが出てくるんじゃないの〜？ もう期待しちゃうよ〜」(Ah, you just saying that to be humble. You just might do a “ultra C” (bring unexpected results to the table) in the coming days. I can’t help but wait..!)
山田くん「いや〜、本当にそんなことないっすよ〜 （本当に何もない… とほほ）」(I really have nothing to hide (and I really mean it… sigh))
When you’re boss starts expecting an “Ultra C”, it’s an indirect (wrapped up in another extra layer of indirect-ness) way to say, “I expect you to do better”…
Hope this helps. happy studying…!