Various Mutant Plants and Animals - Derek Holland

To really bring out the alien nature of Mother Nature on Gamma Terra, gms usually have a list of small, non -combative mutant plants and animals to use on random encounter charts. Here are some that I have come up with over the years: 

Field Voles - these critters are dangerous only to greenfolk and farmers. They seem to be able to reproduce at a rate of 3 -4 young per 2 weeks. 

House Frogs - these amphibians are a major pest to those who store food in large amounts. They can change color and have and sticky feet. 

Steel Rats - they are named so because they can chew through metal and nest in such areas. The Created are terrified of them. 

Nauga - these weasels are immune to radiation. The power is due to their hide, so anyone wearing a cloak of naugahide is immune to R0 -R3, and R4 is treated as R2. In the 4th edition, reduce the radiation intensity by 3/4. 

Log Dwellers - these giant hermit crabs have adapted themselves to forests and use snags as homes. 

Gliding Cat - these felines have evolved the skin flaps that make flying squirrels famous. They can be "domesticated". 

Lake Cow - these genemod cows were used to eat weeds and are now used as cattle by lake dwelling peoples. 

Walking Trees - giant walking sticks that now look like entire trees. The largest can grow to 30 meters. They feed on the surrounding vegetation. 

Stickies - plants that have sticky seeds. They germinate, grow and die in 3 days, all on the object the seed lands on (if it is organic). It causes damage to organic matter (living or formerly living material) and has weakened leather and hide armors. 

And a few by William Wood 

Mule Beetle - Giant mutant beetles, that have been domesticated by farmers. These beetles are quite docile, and have no natural attack. They can perform basic hauling and plowing functions, but are not very bright. 

Flutterfly -(Giant Mutant Butterfly), these mutant insects are quite beautiful. They are harmless and feed upon the nectar of various mutant flowers. Attempts have been made to domesticate them but have so far failed. It is considered bad luck to kill a Flutterfly. 

Steak Wurms - A type of mutant worm. The meat of which is quite tasty, larger specimens can feed a small village. Some Seekers have become Steak Wurm farmers (ranchers). 

Moonbat - Mutant Albino bats, these bats are similar to normal bats, except under the light of a full moon (or similar light source), their fur takes on an eerie glow, this light attracts insects that the bats feed upon.