Magic players who began playing around a certain time - the degenerate environment that was Urza block - remember the name of one particular artifact creature with either fondness or loathing: Masticore. While today it'd merely be considered a fairly strong card - a good but not format-defining rare - at the time, it was the best creature in the game, when other creatures were way less strong than they are now. Back then a 4/4 for four mana was unheard of even in green, and the potential for huge amounts of removal and the regeneration way more than made up for the big drawback of having to discard a card each of your turns. The bizarre monster became iconic and apparently isn't a Dominarian-exclusive design, as a couple of other Masticores showed up in the Mirrodin setting. Mark Rosewater is known to like them, as do some of his Tumblr blog readers.
When mtgraptor asked, "Have we seen the last of my favorite Magic creatures - Masticores ?" Rosewater said there may well be more in the future.
Masticores have a lot of cachet - they feel old-school and nostalgic, and also capture a lot of the mechanical and artistic territory of artifact creatures of yore: scary weapon toolboxes, crippling drawbacks, baffling but charming creative direction. My take on Tumblr: "Masticores are sweet, but why they aren’t Artifact Creature - Manticore on the typeline I will never know. Still, more Thran ones and Mirran ones and Esper ones if we ever see Alara again and Phyrexian ones too."