How about a dark creature that preys on the minds of other creatures that channel? Targets for their attacks would be opposing mages and their familiars. We could use the existing Mana Transfer effect to take pooled mana or transfer mana during channeling from all target creatures in the Arena (or within some range limit). It would not have its own channeling ability, but have a Spawnpoint ability to cast other channeling Mind creatures such as the current Thoughtspore or a new level one type of Thoughtspore.
