Not only does the following, and more, occur when Cuchulain enters his battle rage, but also the following: 1) he is unable to receive injury of any form, 2) though he may slaughter thousands, no blood is ever seen to touch him, and 3) a Battle Hump protrudes from his back.

Cuchulain's battle rage

Before going into battle Cúchulain undergoes a transformation known as his ríastrad [battle fury, battle frenzy, warp spasm, etc.; gen. rístarthae]. When this overtakes him, he becomes a fearsome figure such as never been seen before. Every part of him quivers like a bulrush in a running stream. His calves, hams and heels shift to the front, and his feet and knees to the back, while the muscles stand out like the head of a baby. One eye is engulfed deep within his head, the other protrudes. His mouth meets his ears, foam pours from his jaws like the fleece of a three-year-old whether. The beats of his heart sound like the roar of a lion as he rushes to his prey. A column of dark blood spurts forth from his scalp and scatters in four directions, forming a mist of gloom. Then a projection emerges from Cúchlain's head like a horn but the size of a man's fist; it is the *lón láith/laíth [light of the hero(?)], which signals that he ready to fight.

*lón láith (laoich) [Ir. champions light]. Light beam projecting from Cúchlain's forehead as he goes into battle.