Stalagmite

2nd Level Transmutation

Choose a 5 foot square of space occupied by a creature within range. A frighteningly sharp stalagmite erupts from the stone below to impale the creature standing in the space. The target must make a Dexterity saving throw. On a failed save, the target takes 4d4 piercing damage and is restrained for the spell’s duration. On a passed save, they take half damage and are not restrained.
To break out, the restrained target can use its action to make a Strength check against your spell save DC. On a pass, the target takes 2d4 piercing damage and is no longer restrained by the spike. If the spell ends and the target is still restrained, it takes 2d4 piercing damage and is released as the spike returns to the earth.
A huge or larger creature cannot be restrained by this spell, but takes damage as normal.

Details

Author: Démos Tolmi 
Casting Time: 1 action
Range: 30ft
Components: V, S, M (A small chunk of limestone)
Duration: Concentration, up to 1 minute