To keep access to that effect expensive, WotC dropped it on a 4/5 flying vampire and priced it at 7 mana
Though once content to gorge itself in a ravenous pseudo-hibernation, the rumblings of aether and machinery have drawn her attention toward the surface
It current price is around $0.88
Clawhauser has the Bodyguard ability to protect other low-health characters, but he also counts as 4 towards singing songs and has 2 Quest to boot
The trick is that you can only attack (challenge) characters that are currently gaining victory points (questing) or using abilities (i.e., they are exerted), thereby preventing them from gaining more points
Grolnok is everything you could want from a self-mill Commander in these colors: affordably costed, open-ended in deckbuilding requirements and templated to not lose its accrued value if removed