Symbiotic Mole Leviathan
Just imagine you are in a horse carriage, except the toll can be regarded as somewhat... Unconventional.
Anatomy & Behaviour
This gentle giant of a mole can accommodate up to four medium creatures; two for each meaty flap situated under its huge claws it uses for traversing and digging subterranean tunnels. To enter, one must be willing to sacrifice some life force, usually in the form of a few drops of blood. The mole benefits greatly from the diversity of the life force it consumes - usually prolonging its own lifespan.
When a sufficient toll is provided, the mole inspects the blood with its long snout. The sensitive whiskers surrounding its tear shaped nose loosen to absorb the life force. With entry granted, the mole then invites the weary passenger under its arms. Here, a creature needs to attach itself to some slick appendages to secure themselves. These appendages not only hold you in place during the broad movements of the mole, tiny needles dig into the skin to supply nutrients throughout the journey. This is vital as some trips can last days.
The underground is much safer for travel than the surface in the Chrysid swamps. The surface is full of giant insects and even larger reptiles. Natives have been observed to use these moles to travel between locations of great danger - usually a known hunting ground for the large fauna of the land. With a large enough toll, the mole allows its passengers to also haul some cargo. Not a lot of adventurers are keen on using this mode of transport, however most can attest that it is preferable to crossing an area of certain death.
After it's primary use as a vehicle, some tribes have used it to rehabilitate patients in a coma. The tribe shaman pays the toll for multiple patients so that they can benefit from the nutrient rich fluid injected through the mole's appendages. After a few journeys with the mole, most patients are rehabilitated enough to nourish themselves normally. The practice is not very commonplace but the results are undeniable!
The use of the Mole as a method of healing is a nice touch. I like the method of buying passage, a bit of life essence, some hours or days off your total life and a safe trip is bought.