Yeah Ive seen this Biome before but only in snapshots :/ It is the Ice spikes biome Very rare Also handy as it is the only way to access packed ice other then creative, packed ice is also like an average block just less gripping when walking on it, it is un-meltable and ideal for ice rinks or mini games :I Big ups on Finding it if you're surprised by this you'll get pumped when you see the other biomes introduced thanks to the 1.7 update ^_^