The 2. c3 Sicilian is unlike any other opening in chess

c3 on move 2 against the Sicilian has the idea of playing d4 next move, when Black's playing ...cxd4 will not result in their having an "extra central pawn". 1...c5 prepares to eliminate White's pawn on d4 by using the c-pawn rather than the e-pawn, and 2. c3 perfectly cancels out Black's c-pawn in the fight for the center. In effect, it means that Black has to do move one all over again. I cannot think of another opening in chess that does this. With 1. d4 f5, which looks like the Sicilian "flipped", 2. f3 is a move you will never see. A move 2 that effectively makes your opponent redo their first move, quite an amazing thing!

DISCLAIMER: This does not mean that 2. c3 is a perfect solution for the Sicilian. I make no such claims. In fact, it may be instructive for you to compare and contrast Black's responses to 2. c3 with their other possible first moves and see why Black usually gets an improved version of those openings when White plays 2. c3.