Chamelon Skinks

Skinks can move over marsh, rivers, lakes, or any other water features without penalty, and will benefit from soft cover while in such terrain.

For all Leadership tests, Lizardmen units roll 3 dice and choose the lowest 2 scores

Unit are skirmishers

See page 112 of the Warhammer Rulebook.
In addition, scouting Skinks count as being out of line of sight if they are deployed within a water feature and more than 2" or more from enemy troops as normal

Skink darts and javelins count as Poisoned Attacks (see page 114 Warhammer Rulebook).

Chamelon Skinks work best when stalking their prey alone. Characters can never join units of Chameleon Skinks

Enemies suffer an additional +1 to hit when shooting at Chamelon Skinks.

In addition, Chameleon Skinks are deployed at the same time as Scouts, and can be placed in one of two ways.
Either place them exactly as Scouts, but with no minimum between them and the enemy, or place in sight of the enemy (even in the open) but more than 12" away from them.