Well Black wants to play a Benoni defence after 4.d5. You can play 4.Nf3 or 4.e3 here as well.
1.d4 Nf6 2.c4 e6 3.Nc3 c5!?

Definitely the Benoni in a different move order. Actually it looks like the Modern Benoni... no difference in move order
I saw Hikaru play it once and have messed around with it. When I put it into analysis board it does not have an actual name. Its a unique opening and I stump a lot of my competition on move 3 as they have not seen this before

I saw Hikaru play it once and have messed around with it. When I put it into analysis board it does not have an actual name. Its a unique opening and I stump a lot of my competition on move 3 as they have not seen this before
That "unique opening" is a standard Modern Benoni after 4.d5, and it has been played thousands of times under this move order.
Does anyone know what this opening is called and how to respond to it or variations to it.