title says it all

When I made a Lava pour-er, I made a bucket with an electronic door on it, then I heated up the lava to 3500

I then put my victim man under the bucket which is made of wood, plant, water, a bit of C4, and Glass

I poured the 3500 degree lava onto the man and noticed it made quite a bit of plasma as a biproduct for some reason

what causes this?