**So what is this Defaidodon thing that people are talking about today?**
Defaidodon is a bit of a play on words, with the first part being the Welsh word for sheep (defaid - in this case a plural word), plus the second half of Mastodon, to make a new hashtag. It grew out of some silliness on the Welsh instance toot.cymru around the time when lots of people joined up.
@sheepnik Don't make up any more Welsh words please. The ones you already have are hard to learn and pronounce with old teeth