The achievement Low Thi earns for ruining Carl's quest by killing Wynne — proof, he jokes, that Carl really is Carl.
Cockblock is the achievement Low Thi receives for spearing Wynne and thereby ruining Carl's Free Wynne from his Bondage quest — the notification confirming to Low Thi that the human before him really is the famous Carl.
A comic achievement for spoiling another crawler's quest.
Also appears in books you've already read — spoiler-safe to their endings: