The substance appears to be a rather fluent liquid. But in actuality, it's a viscous colloid of aqueous KMnO4 ( ********* permanganate). The gel-like dispersion of this ionic solid throughout the water exponentially increases the water's cohesion (the H2O molecules stick to each other like a solid while remaining in the liquid state). Look up colligative properties.

The "firmer" substance retains the shape of the ***** because the structure wants to minimize its free energy. It's easier for it to stay in shape than to settle out due to the water's cohesion. However, a slight disturbance will cause it to change state and *snap* it settles.