Colonials are sapient meat blocks that exist mainly to suffer. This pack changes the netherrack and soul soil texture to fields of living human flesh, and the lava to alien waste.

This should work with any version since the nether update.

For more information, read Nemo Ramjet's wacky masterpiece, All Tomorrows. (or check out this excellent narrated summary)

I might change the other nether blocks later, and make the step sound like walking on something squishy.