A little slow on getting this one posted but here’s what I gave the player characters for mounts. They had to earn them thought.
Psychic Riding Cockroaches These large beast scurry about the wastelands in small herds of 3d6 creatures. They are generally non-aggressive and tend to flee at the first sign of any danger. Legends say that the strong willed can tame the beasts and use them as mounts.
Init: +2; AC: 11; Atk: +1; DMG: 1d3 Action Die: 1d20; HP: 20; Saves: Fort: +4, Ref: +2, Will: +2
Special: For their action, a character may attempt to form a psychic bond with a cockroach and turn it into a loyal (as loyal as a cockroach can get) mount. The character must be within 3 feet of the roach and succeed on a DC: 14 Will Save. On a failure, the roach gets a free attack on the player. If the player rolls a Natural 1 then interesting things happen then a psychic resonance effect occurs. The cockroach squeals and it’s head explodes causing 1d6 damage to the character (DC 10 Reflex Save for Half Damage) Also, the character must make a DC 10 Fort Save. If the successful then the character has a splitting headache (-2 to all rolls) for the next 2d6 hours. If the Fort Save fails the following happens. If the character is a Mutant, Plantient, or Manimal then they immediately gain the Taller and Carapace mutations. If the character is a Pure Strain Human then the character is transformed into a Manimal, Subtype Cockroach.