If you’re not a Porter Square local, you might aspire to become one after a visit to Bagelsaurus. The tiny bakery and sandwich shop on Massachusetts Ave. serves up airy, crackly-skinned bagels born from a decades-old sourdough starter. Open early until sellout just Thursday through Sunday with limited online ordering available, a wait in line is rewarded with a baker’s dozen choices baked that day, such as Sea Salt, Cinnamon Raisin, or Black Olive bagels. You can also opt for hearty breakfast sandwiches like the almond butter-banana-honey-bacon T-Rex, or our fave, the zesty Eggspañola (add avocado).