Invasive ground cover
This is lesser celandine, a very aggressive non-native invasive plant that takes over natural and park areas, ruining the ecology for wildlife.
You can dig small patches, but usually this is unsuccessful because a few bulblets get missed and it all starts over again. An herbicide with glyphosate as an ingredient is very effective. Glyphosate is a total vegetation killer, so use a shield of cardboard or plastic to keep spray off your good turf. You'll need to reseed the areas where you eliminated the lesser celandine.
Click here for more help: https://extension.umd.edu/learn/weed-week-lesser-celandine