Taygeta's Supernova

You invoke the collapse of an arcane stellar body, simulating a cosmic death event. Over the course of three turns, the spell evolves—first drawing everything inward, then erupting in a violent supernova, and finally stabilizing into a pulsar remnant that punishes all who enter its influence.

🔹 Stage One: Gravitational Collapse

A 50-foot-radius sphere centered on a point within range becomes the center of a collapsing gravitational field. At its centre, occupying a 10-foot radius sphere is a burning star, pulsing as it futilely attempts to resist collapsing under its own mass. 

• Each creature and unsecured object within the area must make a Constitution saving throw at the start of their turn or immediately upon entering the area. On a failed save, creatures and unsecured objects are pulled 30 feet toward the center, ending this movement as close to the centre as possible, and has disadvantage on any checks made to move away from the center until the end of their turn. On a successful save, No effect.

• If a creature or object touches the star at the centre, it takes 4d10 fire damage. Creatures that attempt to move away from the center must repeat the saving throw. On a failure, movement is halved and requires double movement to escape. You can maintain this stage until you use your action to Trigger the Second Stage.

🔸 Stage Two: Nova Detonation

You may use your action to trigger the second stage. When you do, the star's core finally collapses under gravity, its mass rebounding off its core, and explodes outward in a 30-foot-radius sphere of brilliant light, brutal force, and blistering heat.

• All creatures and unsecured objects within 30 feet must make a Constitution saving throw. On a failed save, all creatures and objects within the radius take 10d10 fire damage and are pushed 25 feet away from the center if they are unsecured. On a successful save, Creatures and objects within the radius take half damage and are not pushed. If a creature or unsecured object's path while being moved due to being pushed is obstructed by a secured object or other unaffected and still-intact obstacle, the creature or object and the obstacle additionally take 3d10 bludgeoning damage. Walls and other structural objects take the full damage unresisted unless they are magical.
  
  Triggering this stage causes the Third Stage to trigger immediately.

🔸 Stage Three: Pulsar Remnant

After the star explodes, your next action is immediately used to cause the spell's area to reduce to a 40-foot-radius sphere, centered on the original point. At its heart spins a blinding arcane pulsar, emitting two beams of radiance rotating vertically at a rate of several times per second while also rapidly rotating clockwise horizontally, filling its area with its radiation. The beams sweep in 40-foot lines faster than virtually anyone short of a divine avatar or a god can react. The area within a 5ft radius sphere is distorted as gravitational effects act like a lens and bend light around the pulsar. Any dust or loose debris weighing no more than 100 pounds within that 5ft radius sphere immediately surrounding the pulsar are forced to orbit around it in the direction of its horizontal rotation and deal 3d12 Bludgeoning damage if a creature enters that radius for the first time in a turn or begins its turn there.

• The area of the 40-foot-radius sphere becomes difficult terrain for the duration as the area becomes an ergosphere caused by gravitational frame-dragging. Within the affected area, darts from the Magic Missile spell must make ranged spell attack rolls, all other ranged weapon or spell attack rolls are made at disadvantage, and all saves against areas of effect from any source are made at advantage. 

• When a creature enters the area for the first time in a turn or starts its turn within the 40-foot-radius sphere, it must make a Constitution saving throw. on a failed Save, the creature takes 6d10 radiant damage and is nauseated (incapacitated, can’t take actions or reactions, spends its turn retching). On a successful Save, the creature takes half damage, suffers no further effect. Constructs and other creatures with no intact organic body parts or which do not eat are immune to the nauseated effects.
  
  This final effect remains until you dismiss it with a free action, you lose your concentration on it, or the spell's maximum duration is reached. If you lose your concentration at any stage, the spell ends.