This one is interesting because I already had a crack at converting the Meteor Stalker, a weird creature brilliantly visualized by Russ Nicholson. Patreon backers can read all about that, but in a nutshell (or a meteoritic geode) it's as follows. The characters see a piece break off Blue Moon, one of five celestial bodies in the night sky over Krarth. The object plummets to earth:
"Concealed in the undergrowth around the clearing, you watch the blue flare crash through the trees at the edge of the clearing and explode in a shower of blue sparks at its centre. The high-pitched whistling noise has stopped, but now you hear a hissing sound from where steam rises from the place where it struck. In the centre of the steam you can see a black stone which even as you watch cracks apart like an egg. An area of darkness spreads like a pool of shadow. Then a hunched shape rises up from the shadow as though taking shape out of the very ground. It is a skeleton dressed in black tattered robes. Its eyes are glowing blue crystals. It seems to sniff the air as it looks around."
And the stats I gave for it are: