The party warlock has a wand of web.
He just leveled to 11th and is considering his choices for his 6th level arcanum.
Scatter (XGtE) allows him to teleport creatures to unoccupied spaces against their will, and he would like to be able to send them to a space with his web or an environmental hazard like fire, slime, or mold.
The PHB uses 'unoccupied' 49 times but never defines what an unoccupied space is, as far as I can tell, and neither does the DMG. The context of dimension door, and the figurine of wondrous power, make it clear that a space can be occupied by at least a creature or object, but do not explicitly say that these are the only things that can occupy spaces.
Does a spell effect or environmental hazard occupy a space?
Best Answer
No, spaces with navigable hazards should not be considered occupied
Any space that you could normally move into and end your movement there cannot be considered occupied, since the most consistent definition of an occupied space that we can infer from the body of the rules is that "something there takes up sufficient space that you can't loiter in that spot". A space with a hazard like fire or web in it might be dangerous to enter or pass through, but there isn't a physical obstruction which prevents a creature from entering and staying in that space - either under their own power or someone else's. Thus, for the purposes of the rules about movement, it doesn't make sense to say that space is "occupied".