This is.. probably my last concept image of Impact. The splatter brushes are by someone on dA but I forgot who.

Impact's body is filled with ink. His blood is ink, and he can shoot ink from his antlers (which is why they're usually stained black). Although his saliva is clear, he has a storage of ink spit at the back of his throat to spit at others if threatened, his second defense mechanism.
His tongue is the length of his body and acts like a worm being able to stretch and shrink at will. However he prefers to keep it short because stretching it out makes him feel vulnerable. However he stretches his tongue out when he's fishing and catches fish by winding his tongue around them and dragging them out of the water. His tongue is very strong and firm, and cutting it off would require a lot of hacking with a sharp axe.