I was thinking that wizard that are in krokotopia would be able to get a mount that is the spiral door, whenever you jumped it would open up and you would have the option to go to another world. It would be like the surfboard mount and you would be able to obtain it as a quest reward or with crowns.
I say it would be a super rare drop from a big important boss like malistare or hades, zues, and posideon. also morganth forgot that one, and maybe darkmoor drop, but one of those