Can a creature under Dominate Person choose to willingly fail the saving throw from Calm emotion if the caster is viewed as an enemy?

The description of the Calm emotions spell says:

You attempt to suppress strong emotions in a group of people. Each humanoid in a 20-foot-radius sphere centered on a point you choose within range must make a Charisma saving throw; a creature can choose to fail this saving throw if it wishes.

If a player controlled by Dominate Monster is asked to kill his allies, could he willingly fail the saving throw since he view them as ennemies and calm emotion could be "dangerous" for him?

Is Corpse Flower the only non-undead that can make an undead creature (excluding spells)?

Is the Corpse Flower the only creature that isn’t the undead-type to be able to make any sort of undead creature?

I mean by means other than the ability to cast spells and one of those spells might be a spell like Animate Dead.

I’m looking for other creature’s abilities, lair actions or diseases or magic items that aren’t simply vectors for spells like a Spell Scroll of Animate Dead.

Where does a creature – flying low over a large body of water – descend when subject to the Earthbind spell?

In looking at the question Can the Erupting Earth spell be cast somewhere that isn’t on “ground”? other examples of spells involving the "ground" could be useful. Or not. Which lead to the question, where does a creature – flying low over a large body of water – descend when subject to the Earthbind spell?

According to the description of Earthbind:

An airborne creature affected by this spell safely descends at 60 feet per round until it reaches the ground or the spell ends. (XGtE pg 155)

Assuming the creature began its turn 60 feet above the water and failed its Strength saving throw, would the spell end:

a) when the creature reaches the water’s surface after 1 round (in other words, is the surface of the water "ground"?), or

b) would the creature continue to descend for the remaining 9 rounds for as much as 540 feet to the earthen bottom of the body of water (see note below), or

c) would the spell fail altogether, or

d) would the creature be forced essentially sideways for the duration of the spell, towards the nearest point of land, or

e) other?

Note re being forced towards bottom of large body of water:

Given a creature with 10 Constitution, 30 ft movement, and no innate swimming speed, its movement in the ocean would be 30 ft using both its Movement and Action to "Dash" (or 20 ft in difficult terrain).

540 ft of total movement would take 18 rounds (27 rounds in difficult terrain) and the creature – assuming it can’t breathe underwater or teleport in some fashion – would be unable to hold its breath after 10 rounds and would drop to 0 hit points after the next round.

’cause if the surface of the ocean is ground, guess what might . . . erupt?

Bane: multiple saves for same creature?

Jed the cleric is standing next to Gideon, his enemy. Jed casts Bane; Gideon succeeds at his saving throw. On Jed’s next turn, he uses the concentrate action to expand the aura and cause all creatures not yet affected to make a save. From Bane:

Once per turn, starting the turn after you cast bane, you can use a single action, which has the concentrate trait, to increase the emanation’s radius by 5 feet and force enemies in the area that weren’t yet affected to attempt another saving throw. Bane can counteract bless.

Gideon already succeeded once. Does he have to make another saving throw?

Grease spell: Can a creature with 10 strength or more jump over the greased area?

The spell Grease does the following:

Slick grease covers the ground in a 10-foot square centered on a point within range and turns it into difficult terrain for the duration. A creature that enters the area or ends its turn there must also succeed on a Dexterity saving throw or fall prone.

Since the affected area is only 10-foot long, can a creature with 10 or more Strength jump over the greased area, thus avoiding both the Dexterity saving throw and the difficult terrain?

For reference, the rules for Long Jump are the following:

When you make a long jump, you cover a number of feet up to your Strength score if you move at least 10 feet on foot immediately before the jump.

How much damage does a creature take if critically failing a Reflex Save with Improved Evasion?

Improved Evasion (available on at least Rogues and Swashbucklers) provides

You elude danger to a degree that few can match. Your proficiency rank for Reflex saves increases to legendary. When you roll a critical failure on a Reflex save, you get a failure instead. When you roll a failure on a Reflex save against a damaging effect, you take half damage.

How much damage does such a creature take on a critical failure? Full or half?

If I want to affect a creature with a concentration spell and it succeeds its save, do I notice my concentration failing? [duplicate]

I’m a fairly new DM, and I’ve run into a problem. One of my players tried to cast Modify Memory on a golem. Golems are immune to being charmed, but Modify Memory doesn’t say creatures immune to charm are unaffected. I decided to let the spell through because of narrative reasons. But, we had a discussion.

Modify Memory says:

On a failed save, the target becomes Charmed by you for the Duration.

The spell is a concentration spell for 1 minute. My question is the following: If I had not let the spell circumvent the golem’s immunity to charm, would the caster know that the spell didn’t affect the target, since it requires concentration, but there’s nothing to concentrate on?

Does a polymorphed creature remember who his friends are?

The polymorph spell states, in part:

The target’s game statistics, including mental ability scores, are replaced by the statistics of the chosen beast. It retains its alignment and personality.

Does retaining its personality suffice to let it remember who its allies are? Even if transformed into something stupid like a T-rex? What does it even mean for a beast with Int 2 to have someone’s “personality”?

How much damage is dealt/taken when that damage also reduces a creature to 0 hit points?

The particular case where this question came up was when a Hobgoblin Warlord attacked my ally, who had 7 hit points remaining. The attack’s damage was rolled for a total of 13, meaning they would fall unconscious. However, I am a Redemption Paladin which means I can Rebuke the Violent:

[…] Immediately after an attacker within 30 feet of you deals damage with an attack against a creature other than you, you can use your reaction to force the attacker to make a Wisdom saving throw. On a failed save, the attacker takes radiant damage equal to the damage it just dealt. […]

The question that arose was how to calculate "the damage it just dealt". Did the Hobgoblin Warlord deal 7 or 13 damage to my ally?

The only thing I found that somewhat answered this was the section on "Instant Death" which includes the following (emphasis mine):

[…] For example, a cleric with a maximum of 12 hit points currently has 6 hit points. If she takes 18 damage from an attack, she is reduced to 0 hit points, but 12 damage remains. Because the remaining damage equals her hit point maximum, the cleric dies.

This seems to state that the Cleric still takes 18 damage, even if her points drop to 0, but then it also states that 12 damage "remains". It’s not what I would call definitive and it doesn’t explicitly state that that is how damage works so I’m wondering if there’s anything that makes this even clearer.