TIL: zombie pigmen are immune to fire and lava. Here's a little proof demo. I wonder how many are just wandering aimlessly round the bottom of lava lakes in the nether? :
Lava Zombie by hellboy12345 on DeviantArt
Return to Vader's Castle #5 Night of the Lava Zombies—Review - Skywalking Network
lava zombie | Minecraft Skin
Challenge map: under a sky of lava, next to a zombie spawner (save the sheep!) - Survival Mode - Minecraft: Java Edition - Minecraft Forum - Minecraft Forum
zombie | Nova Skin
Lava Zombi.. | PLS:
Lava Zombie (Planeshift) - Gatherer - Magic: The Gathering