I saw a mudcrab the other day. http://www.youtube.com/watch?v=QqaFGemOxW0. I'm pretty sure it was a god.
that is hysterical! i love it! as for the OP i had the infamous "mammoth drop" glitch where it drops from the sky. when it hit the ground it died, it was awesome.
back to mud crabs for a second, i found a tiny lake and there were 6 mud crabs there, now mud crabs in oblivion were 1 hit kills so i summoned just one bound sword and was quickly overpowered! yes, i almost died from mud crabs! luckily all i had to do was back up, summon another sword, and gather myself before i was up to my knees (literally) in mud crab.