Mutant Handpan are something kind of new that we've only seen popping up (or at least going by that name) in recent times. And in addition to its twelve notes, this instrument also features a Gudu Hang style udu-port, plus a mandala design on the under-shell.- making it quite the showpiece (you can take a listen below)...
Popularised by the Golden Mutant Handpan of Jan Borren, the Mutant-label appears to refer to the inclusion of a pair of additional “eye-like” notes towards the front of the Handpan. And this specific configuration (that a number of other makers are also now beginning to make use of) appears to have been born when Handpan-musician Kabecao visited Jan Borren at his workshop in the Netherlands - to co-create the instrument that you can hear below...
Though with that said, U.S. makers, Pantheon Steel, have also been experimenting with what they named "grace notes", since as far back as 2012, to similar effect. And with EON-Art having produced THIS "Silver Mutant", featuring only one "cyclops" style additional note, perhaps, for our needs at least, the Mutant-tag will come to serve best as a definition for any non-standard note layout. Though if that also includes the likes of the thirteen note chromatic Spacedrum, and also additions like Booty Taps, perhaps then the term would become too all-encompassing to be useful.
Regardless though, we're liking the Mutants. And for those who enjoy theirs with two-eyes, as per the Kabe/Jan recipe - you can hear another example, this time built by Satya Sound Sculptures, below...
T-U-R-T-L-E-POWER!
As a side-note, if our own experience is anything to go by, their probably isn't a Handpan musician alive who hasn't, while out with Handpan on back, been told that they kind of look like a Ninja Turtle. And for those happy to embrace their turtle-power, and become a bona-fide Handpan-wielding Hero-in-a-half-shell, you could do worse than to check out the totally-bodacious Turtle case from Hardcase Technologies (pictured above). More info available: HERE.