Last year, we got the news that your body is hiding an organ we didn’t know about—the mesentery. Well it’s déjà vu all over again (more ‘Yogi-isms’ here), 2018’s hottest new organ is the interstitium. Scientists identified this web-like system of fluid-filled tissues by using lasers to look into the body. Peeking into the body without cutting allowed the study authors to image this layer of tissues without destroying it, which is why they posit it has taken so long to identify these structures. And they’re not just there for show, scientifically speaking. The organ could play a role in conducting cellular signals, the development of edema, and cancer metastasis. More researchers now need to confirm the finding, which is typical for this science-y stuff.