The last of us: exodus
This takes part 54 years after the events of the first game. In a wartorn decaying city ravaged by the infected the surviving leftovers of several settlements are forced to leave their homes behind after repairing a salvaged small freighter that survived the corroding effects of salt water in a drydock.

Using the freight containers as housing these survivors embarked on an exodus to africa where they assumed it's thin human population back in the old days would make them relatively safe from the infected but upon arrival they were greeted by the likes of which they have never seen.

As expected the fungus wiped out nearly all humans there decades ago but as it gradually started to lose access to human hosts and faced starvation it took an unexpected turn and mutated itself to infect animals instead. This variant is in fact so mutated that it became unable to transfer back to humans however these animals appear as vicious as ever. Needing nutritions for both their parasitic fungus and their own they are a dangerous encounter on the steppes and are best avoided even when armed with sufficient bullets.

The older the animal is the more covered in fungus it is. Even using high caliber weapons it may take several shots to kill a fully grown matriarch