How to reproduce:
Find a savanna or badlands biome.
Set the time to night.
Place a torch on the ground with an unobstructed view of the sky. Preferably with blocks arround to prevent the zombie from scaping (Fig. 1).
Spawn a zombie on top of the torch and watch the zombie burn to death (Fig. 2).
Figure 1. Setup
Figure 2. Zombie burning on the torch
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