... Where's that come from?
Oblivion. Mudcrabs seem to be the utter toast of Cyrodiil; everyone's talking about them.
The guards:
"I've fought mudcrabs more fearsome than you!"
The citizens:
"I ran into a couple of mudcrabs not long ago...annoying creatures!"
"Well at least they're slow, and not too bright.... their pincers are sharp, though."
"I saw some mudcrabs by the water recently. I steered clear of them!"
Even Skyrim's M'aiq the Liar, in a clear mockery of Oblivion's hot topic:
"M'aiq saw a mudcrab the other day. Horrible creatures!"
M'aiq the Liar's thing is that he talks about changes made to newer installments of the Elder Scrolls series, and how people complain about what's been changed. He's shown up in Morrowind, Oblivion, and Skyrim so far.