[Solved] Concentration and the Hex Spell

[Lapertosa]

Need a little help with concentration mechanics, the Hex spell has one of following effect: "AIso. choose one ability when you cast the spell. The target has disadvantage on ability checks made with the chosen ability."

I wanted to use Hex versus Yuan-Ti in order to "disable" their spell resistance and right on the next turn cast something like Hypnotic Pattern, which is that this is also a concentration spell, so how would that work?

Does the Hex disadvantage ends immediately when I cast the new spell or does is ends only on the end of my turn when I start concentrating on the new spell?

[Chronos]

First of all, what you're trying wouldn't work anyway. Hex gives the target disadvantage on ability checks. Saves are not ability checks (and neither are attack rolls). You can use it to make an ally more likely to be able to grapple them, or to make them less likely to spot a sneaking rogue, because those are both based on ability checks. You can't use it to make them more likely to fail a save, or less likely to hit with an attack.

Second, it also wouldn't work. When a spell requires concentration, you have to start concentrating as soon as you start casting it. The enemy's save doesn't come until you finish casting it. So if you did have some spell that hinders saves, such as Bane, the Bane effect would cease before they had to roll their saves against the Hypnotic Pattern.

[Quoz]

Hex is great for opposed checks - grappling, social encounters, stealth, ect. You can even give disadvantage on initiative if you can cast before combat. Just make sure you and your GM are on the same page about the target being aware of the effect. It is especially fun with some sorcerer levels for subtle spell.

[Lapertosa]

Completly forgot it does not include saving throws, thanks guys!