  We perform molecular dynamics simulations of short-range attractive colloid
particles modeled by a narrow (3% of the hard sphere diameter) square well
potential of unit depth. We compare the dynamics of systems with the same
thermodynamics but different bond lifetimes, by adding to the square well
potential a thin barrier at the edge of the attractive well. For permanent
bonds, the relaxation time $\tau$ diverges as the packing fraction $\phi$
approaches a threshold related to percolation, while for short-lived bonds, the
$\phi$-dependence of $\tau$ is more typical of a glassy system. At intermediate
bond lifetimes, the $\phi$-dependence of $\tau$ is driven by percolation at low
$\phi$, but then crosses over to glassy behavior at higher $\phi$. We also
study the wavevector dependence of the percolation dynamics.
