An ovoid (egg-shape) is one possible answer. A smooth blob (to use a very technical term!) is another.
A cylinder would seem to fit the given description
Cube
Zero vertices
a cylinder l
0 vertices 0edges 2 flat surfaces
A cylinder has 2 surfaces (faces), 0 vertices, and 0 edges.
A sphere or torus (a donut).
circle
Not in Euclidean geometry.
A SPHERE has no vertices and no FLAT surfaces
triangular prism
The cube have: -- six (6) faces -- twelve (12) edges -- zero (0) curved surfaces -- eight (8) vertices
A cube has 4 flat surfaces (called faces) and 6 vertices (or corners).
6 flat surfaces - known as faces, 12 edges 8 vertices.
An ovoid (egg-shape) is one possible answer. A smooth blob (to use a very technical term!) is another.
0 edges 0 faces (faces are planar bounded by linear edges) 2 curved surfaces 1 vertex