Highest level spell combos

[Lord8Ball]

Arcane mirage: (non concentration)
1. Starting off he can halve the parties movement without causing himself any harm.
2. Additionally, he can create structures to separate the party and cut them off from sources of light.
3. Turn the ground into water, acid, lava, mud, etc. What's best about this is that these illusions can interact with creatures as if it were real and do damage.
Reference: https://www.sageadvice.eu/2018/06/03...-lake-of-lava/
4. You can then use greater invisibility(or move through the terrain due to truesight) and then start flying around the area casting cone spells (prismatic spray) and retreating through hidden passages big enougph for a skull to move through with the rest of its movement. Also note that since Acerak chooses when he interacts with the illusion he can cast spells through walls.

Demiplane: (concentration)
1. Have a hoard of undead waiting in your pocket dimension as the backup.
2. Have some of the zombies ready actions to grapple someone and toss them into the demiplane before releasing concentration.
3. Spellcasters will have their concentration locked keeping themselves in their home plane. Additionally if they fail their save they are stuck in a room full of zombies again and must waste another high level spell slot to return.

Nondetection: (non concentration)
1. If you mix this with invisibility you will never be seen even by any divination spell even trueseeing(8th level).

Find familiar:(assuming he isn't broke)
1. Familiar scout and decoy.
2. Can cast spells out of a ring of spell storing if he has it.

Glyphs of warding:(also assuming he isn't broke)
1. Bombs and super non concentration buffs.
2. Summon earth elementals for hit and runs. Unseen stalker + mage armor = 17 ac w/ disadvantage to hit.
3. Have command words set up for on glyphs for spell effects(free action)

Guards and wards: (pre prepared trap)
1. A great option to overlap with arcane mirage.
2. Entire area radiates two layers of magic making it hard to target mirage.

Darkness: (concentration)
1. Since he has truesight it only penelizes his opponents.

Teleportation circle: (pre prepared trap)
1. Overlap with mirage arcane to hide it.
2. Glyph of warding to teleport heroes to deadly places like the bottom of the ocean, side of a mountain, underground stone tomb, etc.

Power word pain:(instantaneous)
1. Anti caster and cripples melee.

Mighty fortress:(instantaneous)
1.For lols.

Invulnerability:(concentration)
1. Rip damage dealers.

Mislead: (concentration)
1. Crazy shenanigans with nondetection.

Arcane gate: (concentration)
1. Cast spells at your enemies from another room in safety.

Blink: (non concentration)
Who doesn't want your enemy to be invulnerable to all damage half the time?

Wish?:
1. Casts it in form of a prophesy for something to happen and ensure it comes to pass sometime in the future.
2. Casts tsunami and floods the entire room for 6 rounds as well as mucking up vocal components.

Nystul's magic aura:
1. no cost
2. cast beforehand to hide auras of traps.