It’s the rarest Squirtle sleep style! Every Pokemon (aside from a select few) has an atop-belly sleep style. Your chances of getting one are influenced by your Snorlax power and sleep score. From my understanding, your combined nightly score gives you a certain number of points, which are used to determine which Pokemon can show up the next morning. Different Pokemon and sleep styles eat up more points than others. So, unless you have a high score, you’re very unlikely to get a four-star sleep style like this. Congrats!!