Wall of Perilous Flame and Chilling Tentacles are both Greater Invocations, the equivalent of 4th-6th level spells. I'm already at my TGT-imposed limit on those. If they weren't or I wasn't, I'd totally be taking them...Black Tentacles is a fantastic BC spell, moreso when it comes with cold damage at no extra charge.<br/><br/>I've looked at Weighty Utterance, but it's a bit too situational to spend a feat on for now.