4 ideas
Jan Amos Sangán Dongo, a human veterinarian who specializes in enormous alien animals, is hired to go inside a colossal organism that has engulfed two diplomats, whose loss threatens interspecies relations. He does not fight the creature. He treats it as a patient and uses its physiology, including how it senses, digests, and moves material internally, to navigate it and get the diplomats out alive.
Real giant organisms need a workaround: low gravity, buoyancy in water or dense atmosphere, or a body plan that does not depend on rigid load-bearing structure. Plausible alien megafauna has to be designed around these limits rather than simply enlarged.
Recast a huge, dangerous creature as a clinical case. Then the useful questions stop being how to kill it and become what it eats, how it breathes, what irritates it, and how it expels foreign bodies. Diagnostic reasoning from anatomy and metabolism turns an unknowable threat into a system with exploitable regularities, which is how a veterinarian handles species no one has seen before.
A farcical, crude, joke-heavy story can still get its biology exactly right, and the rigor makes the comedy work better. Much of the humor comes from taking physical and physiological constraints seriously in absurd situations, so the laugh depends on the science being correct. Treating humor as an excuse for hand-waving throws that source of comedy away.