  Double $J/\psi$ production has been observed by the NA3 collaboration in $\pi
N$ and $p N$ collisions with a cross section of the order of 20-30 pb. The
$\psi \psi$ pairs measured in $\pi^- $ nucleus interactions at 150 and 280
GeV$/c$ are observed to carry an anomalously large fraction of the projectile
momentum in the laboratory frame, $x_{\psi \psi} \geq 0.6$ at 150 GeV$/c$ and
$\geq 0.4$ at 280 GeV$/c$. We postulate that these forward $\psi \psi$ pairs
are created by the materialization of Fock states in the projectile containing
two pairs of intrinsic $c \overline c$ quarks. We calculate the overlap of the
charmonium states with the $|\overline u d c \overline c c \overline c \rangle$
Fock state as described by the intrinsic charm model and find that the $\pi^- N
\rightarrow \psi \psi$ longitudinal momentum and invariant mass distributions
are both well reproduced. We also discuss double $J/\psi$ production in $pN$
interactions and the implications for other heavy quarkonium production
channels in QCD.
