from mpl_toolkits.mplot3d import Axes3D
from matplotlib import cm
import matplotlib.pyplot as plt
import numpy as np

fig = plt.figure(figsize=(10, 8))
ax = fig.add_subplot(111, projection="3d")

X = np.arange(-5, 5, 0.25)
Y = np.arange(-5, 5, 0.25)
X, Y = np.meshgrid(X, Y)

Z =-1*(X**2 + Y**3)

surf = ax.plot_surface(
    X, Y, Z, rstride=1, cstride=1, cmap=cm.jet, linewidth=0, antialiased=True
)

plt.show()