In spacetimes with a positive cosmological constant the area of spatially stable marginally trapped surfaces (MTS) has a finite bound. I will prove that any such spacetime containing stable MTSs with area approaching the bound acquire universal properties generically. In particular, they possess `generalized holographic screens’ (i.e. marginally trapped tubes) foliated by MTS of spherical topology, composed of a dynamical horizon portion and a timelike membrane portion that meet at a preferred round sphere S with constant Gaussian curvature and the maximal area. All holographic screens change signature at S, and they develop towards the past with increasing area without limitation. A future singularity also arises. These "ultra-massive" spacetimes may be more powerful than black holes, for they can overcome the repulsive force of the cosmological constant producing a collapsing universe with no event horizon. Examples and implications of this result will be discussed.