I am currently on my 82nd try for a Shell Lizard. My first 50 or so breeds were all 4 elements. I got 2 birdballs and a pegasus from that. My last 32 have mostly been fire, water and air mixtures. I got 2 birdballs and a furball from that. Basically I've been trying for shell since the game came out. I also do not buy gold. So over it.