Mass cannot be created or destroyed in the conventional sense, as it is conserved according to the principle of mass-energy equivalence (E=mc²). While matter can change forms—such as during matter-antimatter annihilation or pair production—total mass and energy remain constant in a closed system. Discussions highlight that the concept of invariant mass is crucial, as it is defined as the total energy in a rest frame divided by c², and is conserved in interactions. The Big Bang theory raises questions about the origins of mass, suggesting that the rules of physics may not apply in the same way at that singularity. Ultimately, the conversation reflects ongoing debates in physics regarding the nature of mass and energy, particularly in extreme conditions.