The wheel body is a useful mutation, allowing for you to be able to deal moderate damage (enough to one-shot a Glickbol) while rolling at the cost of a reduced rolling speed. The Quadruped Legs mutation, as it's name implies, doubles the number of legs the Trebhum has, increasing it's walking speed.

The Quadruped Legs speed increase balances out the reduced rolling speed produced by the Wheel Body.

NOTE: Unlike the Third Eye, the Quadruped legs cannot be combined with other mutations.

The Leaping Legs increase your jump height multiple times over. The Inflatable Body allows for slow falling.

As a pair, the two mutations make climbing cliffs slightly easier. Also, the two combined create the largest jump possible.

The Toxic Trunk modifies the water the Trebhum Water Processor Body converts food items into water.

If you keep a steady flow of food items from your Storage Body Trebhum to your Toxic-Processor Trebhum, you can keep attacking for a theoretically long enough amount of time to kill most creatures.

NOTE: This combination is made somewhat obsolete by the Mixer Body.

Both mutations remove methods of detection used by predators, namely sight and hearing.

Combined, the Trebhum with the mutations can in theory only be detected by Tripoboshes and Onogroshes, two enemies with small detection ranges, and Articulated Angstoks, which have a very small natural range (desert canyons.)

The Rattle and Deimatic trunks allow the Trebhum with the mutation to ward off some predators. The Odorous Skin allows for warding off a smaller selection of predators though does not require an input.

NOTE: The Rattle trunk supposedly works better (I always just used the Deimatic trunk) at warding off predators than the Deimatic trunk, though is obtained much later in the game.

The Webbed feet increase swimming speed and swimming jump height. The Amphibian body prevents stamina loss while swimming.

NOTE: The Amphibian body really prevents stamina change while swimming, so stamina does not increase either.