ICMP packets can be arbitrary length, and there are plenty of tcp-over-icmp tunnels.
There was this article a long time ago about using packets in transit as storage/memory, mischeivously for free.
Turns out this is how early memory worked, i think it was called delay line memory, made of mercury, i think PDP and DEC era
ICMP packets can be arbitrary length, and there are plenty of tcp-over-icmp tunnels.