The Trickery Domain cleric (PHB p. 62-63) gains the Invoke Duplicity ability as a Channel Divinity option at 2nd level:
Starting at 2nd level, you can use your Channel Divinity to create an illusory duplicate of yourself.
As an action, you create a perfect illusion of yourself that lasts for 1 minute, or until you lose your concentration (as if you were concentrating on a spell). The illusion appears in an unoccupied space that you can see within 30 feet of you. As a bonus action on your turn, you can move the illusion up to 30 feet to a space you can see, but it must remain within 120 feet of you.
For the duration, you can cast spells as though you were in the illusion’s space, but you must use your own senses. Additionally, when both you and your illusion are within 5 feet of a creature that can see the illusion, you have advantage on attack rolls against that creature, given how distracting the illusion is to the target.
Can the illusion from Invoke Duplicity do things such as fly up in the air, appear to jump over a 20-foot chasm, or pass through a cage's metal bars, even though the cleric controlling the illusion could not physically do such things?
In short: does the illusion have to obey any laws of physics?
Best Answer
Yes, the illusory you has more mobility
Absolutely! The only requirements for Invoke Duplicity are (PHB, 63):
There are no restrictions except for total move of 30' per bonus action and a limit of 120' from you. It is simply an illusion and doesn't obey the laws of physics - just the laws of the Channel Divinity.