By speaking the command word of the iron flask, the user could trap a nearby extraplanar creature inside it for an indeterminate amount of time. It was possible for the creature to resist being trapped, and creatures that had been trapped before were harder to imprison again.
Upon removing the brass stopper, the imprisoned creature was released and bound to obey the owner of the flask for one hour, after which it would be free to act as it pleased.
- ↑ 1.0 1.1 1.2 1.3 1.4 Mike Mearls, Jeremy Crawford, Christopher Perkins, James Wyatt (2014). Dungeon Master's Guide 5th edition. (Wizards of the Coast), p. 178. ISBN 978-0786965622.
- ↑ Christopher Perkins (September 6, 2016). Storm King's Thunder. Edited by Kim Mohan, Michele Carter. (Wizards of the Coast). ISBN 978-0786966004.