D&D 5E wisdom vs constitution save

[ECMO3]

But even there, it's tricky, because all saves are not created equal. Sometimes you fail a save and fall prone. Other times you fail a save and get your mind obliterated, after which a brain with paws will jump into your skull and pilot your body to attack your friends. And I don't think it's safe to assume that the distribution of minor vs. major effects is equal between the saving throws.

so there is the frightened condition for characters and the there is a different frightened conditon for players and intelect devourers realy hit that spot. trying to keep emotion out of it!