Learn English – Word for not just taking credit for someone else’s work, but believing that you’re also the hero

So, there's taking credit for someone else's work, and then there's a kind of credit taking that is merged with ego in certain way, and I'm trying to find out if there's a word for this.

It's when, say, a team of people do 99% of the work to get something done. Then someone else comes along, drops the last 1% in to make everything fit together, yet the person who only contributed the 1% walks away convinced that without them nothing would have been accomplished. It's the ego that you not only took credit, but believe that you swept in at the last minute, like a hero, and miraculously saved the day. However, the reality is closer to being in the right place at the right time, but if you hadn't shown up that last 1% still would have fallen into place, it just would have been someone else.

So … is there a word for that specific kind of credit taking, combined with the ego that makes one believe they were the hero?