For a spherically symmetric spacetime, $g_{tt} = 1- 2\Phi(R)$, black hole and Buchdahl star are respectively identified by $\Phi(R) = 1/2, 4/9$. The latter is the most compact object without horizon. We would demonstrate that it mimics almost all black hole features like the maximum force, Smarr formula and the first law of black hole mechanics for charged/or rotating objects. I would also briefly touch upon some of my other recent works on how do rotating black holes form, and overspinning and/or overcharging of black holes  in higher dimensions.