Why do stocks pump on massive volume, and then retrace to the original price?

For example, sometimes I'll see a massive surge in a stock from – for example – $60 to $90 on huge volume on massive news like “XYZ company in talks to partner with mega AI company AIGoogleTelsa to build massive AI data center infrastructure”. More buy volume than the stock has seen in months, perhaps years. Every analyst on Wall Street raises their price targets, initiates “Strong buy” ratings. Then the buy volume just stops. And then the low volume pullback happens. Very little selling, just slow trickle sells, but no buy pressure at all. Then the stock ends up retracing back down to $60. But it's $60 again and there's no buying at all. Why? Everyone wanted to buy it at $60-70-80-90 with more buying volume than the stock has had in years in the matter of 2 weeks, but now that it's back to $60, no one wants to buy it anymore? Then it just sits at $60 for months and barely moves with anemic low volume, sometimes even going lower than $60, even though massive catalysts are in the works. What? I don't get it?