Step 1: Use this in a repeat command block (I used it in a function, so I'm not sure if that changes anything):
/summon area_effect_cloud ~ ~2 ~

{Particle:"mobSpell",Radius:0.5f,RadiusPerTick:0f,RadiusOnUse:0f,Duration:1,DurationOnUse:0f,Age:0,WaitTime:0,Color:10475501}

Step 2: Die with the AOE cloud spawning in view (If I'm right you should see FPS drops even if they are not in view)

You may notice that the AOE clouds keep spawning and causing the world to lag, even though there should be only 1 alive per tick

There is a screenshot of the AOE clouds beginning to spawn constantly but not despawning while I'm dead