After Spider-Man, Iron Spider, and Agent Venom defeat Doctor Octopus, they take him to be imprisoned at the Tri-Carrier where Doctor Octopus uses one of his miniature Octo-Bots to hack into Swarm’s nanites where it starts rebuilding the Tri-Carrier as HYDRA Island. This was all part of Doctor Octopus’ partnership with the recently-freed Arnim Zola that also includes Goblin Formula-enhanced HYDRA Agents