Should I put my entire 401K into Gamestop (GME)?

I don't have a very good understanding of the stock market, but I know that's a bad idea. From the very little research I've done, this huge surge in Gamestop stock is only temporary. Unless you have a good understanding of the stock market I wouldn't invest anywhere near that amount of money.

Only if you want to lose it

You usually cannot put your 401K into ONE stock. You can put it into one FUND--which is also just as stupid--but you can't specify what stocks your fund invests in. And if you're talking about withdrawing it and buying Gamestop stock, for crying out loud--get some intervention for delusional behavior because that's one of the stupidest things you can do. You'll pay penalties, taxes and lose your retirement completely--and if you're not at your fund's distribution age, you won't be able to withdraw the entire amount anyway. 

No 1 stock, MF, or ETF should be 100% of your 401k. 

No.  I'm saying that not because of anything about Gamestop in particular, but simply because you shouldn't put your entire 401K into any one stock.

Yes. Idiots need to lose money.

It's really unlikely that a putting your 401K contributions into an individual stock unless it's the employer's stock or that of their large customers is an option. 

Very bad idea..........................