2024 rules reference for Cape of the Mountebank.
Wondrous Item
This cape smells faintly of brimstone. While wearing it, you can use it to cast Dimension Door as a Magic action. This property can't be used again until the next dawn.
When you teleport with that spell, you leave behind a cloud of smoke. The space you left is Lightly Obscured by that smoke until the end of yournext turn.