Actually, that is a lie. This is the deck I played in my second Call of Cthulhu tournament ever (which was held on Halloween at Wheelers in St Neots). The deck I played in my first tournament was awful and lost every single game it played and I'm really embarrassed by it.
Anyway, this deck is Mono-Cthulhu with heavy emphasis on the Deep Ones. Here is the list:
3x Ravager from the Deep
3x Deep One Rising
3x Deep One Scout
3x Lord of Y’ha-nthlei
3x Adult Deep One
3x Backwater Deep One
1x •Cthulhu, Lord of R’lyeh
3x •Hydra, Mother of the Deep
1x •Julia Brown, Oddly Amphibious
3x Diseased Sewer Rats
3x Dreamlands Fanatic
3x Shadowed Reef
3x Deep One Assault
3x Sacrifical Offerings
3x Pulled Under
3x Touched by the Sleeper
3x Tcho-Tcho Talisman
2x Get if Off!
1x In an Unmarked Grave
The deck was thrown together at the last minute (I was working on a Dark Young deck that never really saw the light of play) and the general gist is pretty simple: play some Deep Ones, blow up anything you don't like the look of and if the Deep Ones die, fish (pun intended) them out of the bin with Hydra.
A few bits and pieces of interest:
Lord of Y'na-nthlei makes Deep One Scout much better - you now effectively only exhaust 1 Deep One to play another for free.
Hydra can help make times where Julia bins something decent less off an issue - you can always get any characters back.
Your opponent's face is priceless when you elect to go second and then manage to play a character for free in his first turn (Sacrifical Offerings + Dreamlands Fanatic).
Touched by the Sleeper and Tcho-Tcho Talisman are primarily in there to help get Pulled Under to work. However, Deep Ones have a bit of trouble with Terror struggles, so both Touched by the Sleeper and Tcho-Tcho Talisman can help stop them gibbering. Shadowed Reef is another obvious inclusion for getting past Terror struggles, but I've found that Shadowed Reef gets targeted with all the Support card hate my opponent can muster.
All in all, the deck did alright and was a lot of fun to play. I was the only guy there not playing with yellow cards and so didn't do very well (won 1 lost 2) but hey, I had fun and that's what counts, right?