Undead Behemoth

You call forth countless dead, drawing them towards you in a storm of flailing bodies. The dead surround and enclose you in a massive, humanoid-shaped undead mass with you at its heart. The resulting undead creature is Gargantuan in size and under your direct control. The undead behemoth has the statistics of a Zombie Giant as shown in my New Monsters post.

While inside the behemoth, you are suspended 20 feet above the ground surrounded in a cage of corpses. Ranged attacks against you are treated as if you had three-quarters cover (+5 AC) and you gain resistance to bludgeoning, slashing, and piercing damage.

The spell ends prematurely if the behemoth is reduced to 0 hit points. When the spell ends, the undead return to death and slowly fall away leading you safely to the ground below, surrounded by piles of corpses.

source: noblecrumpet-dorkvision.tumblr.com/post/179396241811/necromancer-week-new-spells

Zombie Giant

A zombie giant, much like one of a more manageable size, is stupid and driven only by a mad hunger for the living. Necromancers that create them are irresponsible in the best sense and insane in the worst. The creatures will break any nonmagical barrier trying to contain them if they think it will lead to a meal on the other side.

Sometimes a reanimated giant is a secret weapon. A powerful spellcaster can contain one in a magic circle only to be released when the time is right, wreaking havoc on a battle once thought won.

Huge undead, chaotic evil
Armor Class: 15 (patchwork armor)
Hit Points: 163 (13d12+78)
Speed: 40 ft.

STR 25; DEX 9; CON 22; INT 1; WIS 3; CHA 4
Saving Throws: Str +11, Con +10, Cha +1
Skills: Athletics +11, Perception +0
Immunities: poison
Condition Immunities: exhaustion, poisoned
Senses: darkvision 120 ft., passive Perception 10
Languages: Understands the languages it knew in life but cannot speak
Challenge: 9 (5,000 XP)

Actions

• Multiattack. The zombie makes two slam attacks.
• Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., one target. Hit 25 (3d12+6) bludgeoning. A Large or smaller creature hit by this attack must succeed at a DC 18 Strength saving throw or be knocked 20 ft. in a random direction away from the zombie and take 7 (2d6) bludgeoning damage.