This was few years ago, I was an intern in the company (first job I ever had). After few months of fiddling around stuff (haven't yet touched a production project). We landed a 'high priority' project.

We were told by the client (A multinational company) that they had a contract that fell through with another software house and the app is already made they just need to integrate it inside their main app instead of having it a separate app.

We were like, okay, and we made sure that everything will stay the same (APIs, Feature flows, etc). My managers gave it an estimate of two months.

And after a couple of weeks they started changing everything (APIs, flows, design, ALL OF IT) and they insisted we meet the deadline. It was a project for a multinational telecom company so it had payments, features for user's consumption and a shit-ton of other features.

At some point I was the only developer working, had to pull more than 16 hours a day to meet the deadline but we did.

I was in my fourth year of college as well. It was crazy.

May not be the craziest deadline overall, but for sure was the craziest deadline for me to meet.

Edit: Oh and after all of that it was never released bc of "financial reasons"