  The three-dimensional emergent magnetic field $\textbf{B}^e$ of a magnetic
hopfion gives rise to emergent magneto-multipoles in a similar manner to the
multipoles of classical electromagnetic field. Here, we show that the nonlinear
responses of a hopfion are characterized by its emergent magnetic toroidal
moment ${T}^e_z = \frac{1}{2}\int (\textbf{r}\times \textbf{B}^e)_z dV$ and
emergent magnetic octupole component ${\it \Gamma}^e =\int [(x^2+y^2)B^e_z - xz
B^e_x - y z B^e_y] dV$. The hopfion exhibits nonreciprocal dynamics (nonlinear
hopfion Hall effect) under an ac driving current applied along (perpendicular
to) the direction of ${T}^e_z$. The sign of nonreciprocity and nonlinear Hall
angle is determined by the polarity and chirality of hopfion. The nonlinear
electrical transport induced by a magnetic hopfion is also discussed. This work
reveals the vital roles of emergent magneto-multipoles in nonlinear hopfion
dynamics and could stimulate further investigations on the dynamical responses
of topological spin textures induced by emergent electromagnetic multipoles.
