Admittedly, I am not familiar with Muk's taste as it's a Pokemon not commonly found in Unova in comparison to Hoenn and other regions. [However...] That said, I do know that it's a poison-type Pokemon, so you'll want to be extremely careful in regards to touching them, as the sludge it secretes from it's body has a toxic flavor, especially in regards to any plant-life that comes in contact with it.

[... Speaking of which, that might be why Pansage has stayed up here clinging to Cilan rather than climbing down and getting closer to the other Pokemon when greeting it right now.]