It’s a great spell even considering concentration, but why does it use your concentration if the patterns only appear for a moment?

Quote from Tyranthraxes >>

Casting Spellwords are:

Anodyne Exemplar

 Fun fact: this spell doesn’t require verbal components. So no spellwords

Quote from Roary_the_Ravager >>

It’s a great spell even considering concentration, but why does it use your concentration if the patterns only appear for a moment?

The implication is that the pattern of colours triggers some form of hypnosis, so your concentration is required to keep them from snapping out of it. I would think of it like you're preventing them from noticing their surroundings, i.e- no distractions.

That said, I like to think of the pattern of colours as only vanishing for unaffected creatures, i.e- the affected ones are still dumbly staring at swirling patterns that nobody else can see. This is just my own custom head canon though.

Yep.  Spell only does what it says it does.  Effects only do what they say they do.  Never try to read other things into spells or effects.  

yes

What is the save? As it is written i have no idea wha the save is? Is it 8? 16? 10 + your own wisdom?

It depends on who is casting - most of the time your spell save DC will be 8 + proficiency + spellcasting ability modifier. 

So for a level 5 wizard with 16 intelligence their save DC would be 8 + 3 + 3 = 14

Thank you.

Quote from Darkstar_Aurora >>

Do creatures with Truesight simply ignore this spell?  While it is not a typical visual illusion in the sense of invisibility or magical disguise, it still is a visual effect and does belong to the illusion school..

Truesight allows a creature to automatically succeed on saving throws against visual illusions within range. So practically, yes, they would ignore this spell.

Looking at the Available For list, it shows Moon Domain.  Is that a cleric domain or something else? Can't find Moon Domain as a divine domain on the Cleric class.

I don't get why everyone is saying this is OP or needs to be nerfed, when some races get resistance to charm.

The Moon Domain is from the Tal'Dorei Campaign Setting Reborn book. So it has to be bought in order to use it here on DnD Beyond

interesting aspect of being incapacitated is you can still use a bonus action

Here is a scenario.  Mage casts HP at group of enemies.  All fail their saves except ONE - should the one that makes it be able to wake up on more, who wakes up one more, who wakes up one more, etc all in the same round?

Quote from DaMojo >>

Here is a scenario.  Mage casts HP at group of enemies.  All fail their saves except ONE - should the one that makes it be able to wake up on more, who wakes up one more, who wakes up one more, etc all in the same round?

Yes, though remember that "waking up" one of the others takes a whole action to do, meaning they can generally only do it on their own turn and they can't do much else on that turn. So in this scenario, they've spent a whole round waking each other up and not dealing with whatever threats the caster's friends are posing.

Quote from Roary_the_Ravager >>

Quote from Tyranthraxes >>

Casting Spellwords are:

Anodyne Exemplar

 Fun fact: this spell doesn’t require verbal components. So no spellwords

Glances at Material Component 
Laughs in Hexblade

And it is one of the increasingly rare save-or-suck options -- no off-ramp with saves at the end of every turn. The conditions for ending it allow a lot of mischief -- you can (gently) pull people off horses, tie them up, take their weapons, and/or escort them to a cage or over the edge of cliff. None of that damages them!

If Hypnotic Pattern twists through the air, is it possible for it to effect creatures that are in the Darkness Spell??

> Each creature in the area who sees the pattern must make a Wisdom saving throw. 

Does this mean even the caster is affected if they are in the area and forgot to close their eyes?