A thunder lizard is a heavy-set, large lizard that is the distant relative of the kodo. They are aggressive beasts that prefer canyons and plains. When in combat, they shoot lightning from their mouth at distance and dole out harsh headbutts at close range. Thunder lizards come in a variety of colors, including blue, pink, and gray, and live in Durotar, the Barrens, Stonetalon Mountains, and Desolace.
Fighting thunder lizards
Attacks which interrupt the spellcasting of NPC's--such as the rogue's Kick, the shaman's Wind Shear, and the warrior's Shield Bash--are also effective against these lizards. When you see the lightning building up in its mouth, hit it with your class's interrupt ability and you won't have to worry about getting hit by any lightning bolts...you'll only have to worry about being trampled, gored, or crushed by a huge and irate reptile.
Thunder Lizards are hostile, whereas most kodos are neutral and will not aggro unless attacked.
In Warcraft III, thunder lizards apppeared in a variety of forms, including storm wyrms and lightning lizards. Rather than shooting lightning from their horns, they shot it from their mouths. The salamanders and thunder lizards looked very similar, indicating that they are, perhaps, related somehow, as one or the other was a simple reskin of the first.
Thunder Ridge holds a massive amount of thunder lizards, and have already appeared in The Frozen Throne bonus campaign (starring Rexxar). In Warcraft III, Thunder Ridge thunder lizards were green, but in World of Warcraft they are red-skinned.
Spikes in the back of thunder lizards are similar to stegodon ones; but where the stegodon spikes probably serve to help regulate the body temperature (in a similar way that those of the real-life Stegosaurus supossedly did), the use of the thunders lizard ones are unknown. They may be used to channel electricity.