If you think that's wild, just wait until you learn about 6to4 [1] (not to be confused with 6over4 [2] ...)
TL;DR: Given a globally unique IPv4 address, you can create automatic tunneling IPv6 networks with the IPv4 address embedded into the IPv6 address space.
TL;DR: Given a globally unique IPv4 address, you can create automatic tunneling IPv6 networks with the IPv4 address embedded into the IPv6 address space.
[1] https://en.wikipedia.org/wiki/6to4
[2] https://en.wikipedia.org/wiki/6over4