Picture a black hole as a funnel in a taut sheet — the classic analogy for spacetime curvature caused by a massive body. But if a fifth dimension exists, this simple picture gets complicated: the sheet gains hidden springs. Now any mass, even an electrically neutral one, depresses the fabric of space not to a singularity but only to a well-defined limit. Nonlinear corrections to curvature emerge, giving rise to a new kind of black hole with an inherent minimum mass — a property unthinkable in four-dimensional general relativity.

The big surprise concerns thermodynamics. When such a black hole reaches its limit, it does not cool to absolute zero. Its entropy, a measure of hidden disorder reflecting the number of possible internal microstates, does not vanish as standard theory would require. Instead, a finite, nonzero remnant remains. The universe may be littered with invisible warm cores — remnants of evaporated black holes that retain memory of hidden dimensions, like a frozen echo of the fifth dimension.