This is a neat new feature in SSMS, Live Query Statistics. Not entirely useful, but it helps visualize how query execution. This generates a live action query plan so to speak and can be helpful in troubleshooting query development. The query running will naturally occur some overhead by having to generate live query plans, so do not expect tip top performance when using this feature, and certainly take your normal precautions when running this...don't do this on a highly active production system.
I recorded a brief video of this in action:
There are a few limitations to Live Query Statistics. Queries using columnstore indexes and memory optimized tables are not supported. Additionally, Natively compiled stored procedures are not supported.