  Multiple viable theoretical models predict heavy dark matter particles with a
mass close to the Planck mass, a range relatively unexplored by current
experimental measurements. We use 219.4 days of data collected with the XENON1T
experiment to conduct a blind search for signals from Multiply-Interacting
Massive Particles (MIMPs). Their unique track signature allows a targeted
analysis with only 0.05 expected background events from muons. Following
unblinding, we observe no signal candidate events. This work places strong
constraints on spin-independent interactions of dark matter particles with a
mass between 1$\times$10$^{12}\,$GeV/c$^2$ and 2$\times$10$^{17}\,$GeV/c$^2$.
In addition, we present the first exclusion limits on spin-dependent
MIMP-neutron and MIMP-proton cross-sections for dark matter particles with
masses close to the Planck scale.
