This type of black hole is similar to dark matter, in that it warps local spacetime, but at the surface, the gravity is null, there's a weird spacetime topology

This type of black hole is similar to dark matter, in that it warps local spacetime, but at the surface, the gravity is null, there's a weird spacetime topology to it, from what I can understand (I am not a physicist). It would be invisible, and any mass that went in would see an equivalent ejection of energy out, and the form of that energy would be fascinating. If you shot a planet into one of those at relativistic speeds it'd be a totally different, more catastrophically massive explosion than anything we've ever seen, and the volume of space around it would present opportunities to study extreme energy physics. One of the weird features is that because it cannot contain any more energy or mass, it has to immediately expel any additions, so the form of the energy coming out would be interesting to observe.