<prompt> Human: 2 weeks ago someone wrote a post about going all out on 401k and becoming a 401k millionaire before 35.He was kinda rude in his post, but the idea of just maximizing 401k was in my head.If i were to put like 50k in 1 year, what would happen?  <response>: You would owe an excise tax of 6 of the excess amount each year it remains in your 401k.As others have said, its unlikely that youd be able to do this, but there are a couple ways it could happen.At least thats my understanding. IANA CPA, etc. 