At my first job as a dev, after about 2-3 weeks in, my team got a new member. Him and I were the only devs in that team. Supposedly he had 1 year professional experience of C++. After about a week I started noticing he was slow, he also wrote down basically everything I said, if I said I needed a bathroom break he almost wrote that down too.
During a break he asked me; what's a constructor?
Needless to say I was doing both his and my job for 6-7 months before someone else realized he was useless and removed him. Since I was new I didn't know how to react, do I tell anyone? :-/
On the bright side, I learned a lot and we still delivered well before the deadline.