There is, in Adventurers League Dnd, a monster statblock with the following ability :
At the start of his turn, every living creature within 100 feet must succeed on a DC 15 Constitution saving throw or they lose 5 hit points and [he] regains 5 hit points.
That monster also has an ability to spawn Swarms of Rot Grubs (Medium swarms of Tiny Beasts). I am thus wondering how those two abilities interact.
More generally : how are swarms considered vis-à-vis creatures ?
- Considered as a single creature [here, would be a single CON save]
- Considered as many creatures (how do you say how many?) [here, would be X CON saves]
- Considered as no creature [here, would be 0 CON saves]