Teevan's Deathly Steed

This spell summons an undead steed. The summoned creature is a warhorse skeleton or any other resonable undead animal of a size that can be ridden by you, the creature still has the same statistics of the  warhorse skeleton. The steed has an extra AC that is equal to half the level the spell was cast, ronunded down.

The steed is friendly to you, it lets you ride itself and you can mentally command it as a bonus action, in combat the steed shares your own initiative, but you can choose to make it act before or after you. You decide what action the steed will take and where it will move during its next turn, or you can issue a general command, such as to reach a specific location. If you issue no commands, the steed only defends itself against hostile creatures. Once given an order, the steed continues to follow it until its task is complete.

When the steed drops to 0 hit points, it disappears, leaving behind no physical form. You can also dismiss your steed at any time as an action, causing it to disappear. Casting this spell again summons the same or a different steed, with maximum hit points.

You can't have more than one steed summoned at a time. As an action, you can release the steed at any time, causing it to disappear.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher the steed gains an extra 1d10 hit points per spell slot above 2nd. If you cast it at 4rth level or highier the steed becomes resistant to non magical slashing, piercing and bludgeoning damage and it gains a +1 bonus with attack and damage rolls. At 6th level or highier it gains resistance to necrotic damage and it gains a +2 bonus with attack and damage rolls. If you cast this spell at 8th or 9th level it gains a resistance to magical slashing, piercing and bludgeoning damage and it gains a +3 bonus with attack and damage rolls.