I have Dr. Zhark's Mo' Creatures mod, and the turtles on it have a bad habit of glitching. It has happened three times already. The turtles are glitched into behaving like a tamed wolf, a horse and a rabbit (these are also from the mod).
The turtles are normally smaller than one block, but my turtle, Shroomy, grows like a baby horse. He is now 2x2 blocks and 1.5 blocks high. He follows me anywhere, but he doesn't teleport like a wolf. You can also put him on your head like a rabbit, where he looks like a giant turtley sombrero. I accidentally hurt him a few times, but then I used throwing potion of instant health and that did the trick.

Please tell me if you have ever experienced this, because I want to know if my computer or mod version is just screwed up or not.