Make the 3 different flavors of gelatin according to the package instructions, except use 1 cup of hot water and ½ cup of cold water for each box. Pour each mixture into a separate small-medium rectangular plastic container and refrigerate for a minimum of 4 hours, preferably overnight, to set fully.

Make the milk gelatin. Pour the unflavored gelatin into a small bowl and add 1 cup of cold water. Mix together until dissolved. Let it sit for 10 minutes until it solidifies.

While that is sitting, pour the half-and-half, sweetened condensed milk, evaporated milk, and vanilla extract into a blender. Pulse until fully combined.

Microwave the unflavored gelatin mixture for 30-40 seconds until it turns to liquid again. Pour it into the blender with the milk mixture, and pulse a few more times to combine fully.

Lightly coat the inside of a bundt pan with cooking spray.

Gently remove the 3 flavored gelatins from their molds and onto a large cutting board. Slice them into 1-inch squares.

Assemble the gelatina. Add a little of the milk gelatin into the bundt pan so it covers the bottom, then add a layer of different color gelatin cubes, add more of the milk, mixture, and continue layering until all the gelatins are used.

Refrigerate for at least 4 hours, preferably overnight, to fully set.

Gently loosen the gelatin from the sides of the bundt pan, including the inner tube, using your finger. Place a large plate over the mold and flip it over. Slowly remove the gelatina from the mold and transfer it onto the plate. Slice and serve.