He is one of the greatest animals in all of fiction, and easily the greatest dog from comic books.
And he makes everything about the Superverse better by his mere presence.
He is Krypto, the Super Dog.
I was surprised that, 3+ years into these rebooted forums, I can't find an existing Krypto appreciation thread. If there is one, please merge. If not, then let's get it started!
Dogs are awesome. Krypto is super awesome. He is inherently goofy (a flying dog with a cape? come on), but that goofiness endears him to me. More than that, it further endears Clark and his world to me (not that HE needs any help there).
Krypto has been around since 1955. He actually pre-dates the start of the Silver Age and Barry Allen's debut.
While he has yet to make it to any live-action venues, he has made it other media. Heck, he's even had his own animated TV show (2005-2006's KRYPTO THE SUPERDOG) that ran for 2 seasons:
He humanizes Clark in a particular way that no one else does or can.
So All Hail Krypto!* Show him who's a good boy!
* - just Krypto, no other Super-Pets or other Super Animals here