Is there such a thing?

Yes, referred to as hollow points or open tip match (OTM).

They don't expand like pistol hollow points.  The tip cavity is for aerodynamics.  That's why they usually use the term open tip.  The Russians say hollow point, but I think they're the same.  Expanding bullets in the 556/223 world are the polymer tipped varmint bullets.

Not all expanding bullets are polymer tipped, some just have exposed lead.

No real need for hollow points (for expansion/tissue damage) at rifle bullet velocities.

Those little bullets make some nasty wounds.  Don't know how "deep" they'd penetrate, but compared to a ground hog's head/body they do massive damage.

I've shot them in the back of the head at ranges of over 100 yds. but less than 200 and there's no eyes, lower/upper jaw - just a big red gory hole  that bleeds like a 4 or 5" wide paint brush for the first 8 or 10 feet they run (run in whichever direction they hit the ground at.)  They're dead, they just don't know it and the brain/spinal column weren't hit so shock/blood loss gets'em after a few feet.  Done it twice.  Same results both times.

Dosen't sound like a humane kill

Okay I'm an idiot.  Soft point, spire point have exposed lead at the nose and also expand.  The varmint bullets give explosive expansion without penetrating much.  The conventional expanding bullets do so more slowly.  I completely forgot about that style of bullet.

Doesn't get much more humane than instant death, though.

Real life isn't like hollywood. For a creature to die in less then ten or fifteen seconds would pretty much require the brain to be turned into bits and pieces. So for those groundhogs to die that quick is quite humane.