Step 1: Plan:
Subtract the area under the curve from the enclosing rectangle.
Step 2: Steps:
Rectangle with corners at $(0,0)$, $(2,0)$, $(2,8)$, $(0,8)$ has area $16$.
Area under $y = x^3$ from $0$ to $2$ is $\frac{x^4}{4}\Big|_0^2 = 4$.
The wanted region is the rest: $16 - 4 = 12$ square units.
Final Answer:
The area is $12$ square units, option (B).
\[ \boxed{12} \]