The Creature Wiki:Banning

Administrators can block users and individual IP addresses (or IP ranges; see here). Blocked users or IP addresses will still be able to read the wiki, but will not be able to edit, upload files or add comments (and sometimes, disable talk page access).

Users can be blocked for many reasons. Each wiki may have slightly different blocking policies, but in general, blocks are given for:
 * Repeated vandalism.
 * Breaking policies.
 * Adding pages that are copyright violations.
 * Misleading usernames
 * Explicit usernames, pictures, and/or language