Mix the Kool Aid powder, sugar, and water in a bowl until the sugar and powder are fully dissolved and the mixture is vibrant in color.
Pour the mixture into a shallow dish or tray, spreading it evenly to promote quick freezing.
Place the dish in the freezer and let it freeze until firm, about 2-3 hours. Every 30 minutes, stir the mixture with a fork to break up ice crystals and create a smooth, slushy texture.
Once the mixture is fully frozen and has a semi-icy, crystalline texture, break it into chunks and transfer them to a blender.
Blend the frozen chunks on high speed until the mixture becomes a smooth, icy slush with a vibrant color and a slightly granular texture.
Pour the slushie into glasses, garnishing with fruit or a colorful straw for an added fun touch.