Ectoslime

Ectoslime were giant slug-like creatures that stunned their prey with its odour before liquefying and drinking them. They communicated verbally and had a highly developed sense of humour to compensate for their appearance.

Of an alternate Earth, Ectoslime were used in fights in the Rome Hyp-Arena. They were very popular with the crowds, with its own admirers known as "Eccy fans". The Doctor was thrown to one, but he avoided death by telling it a joke. (DWM: The Iron Legion)