[3.5 Monster] The Unseen Bounder (or Chameleroo)

[SovelsAtaask]

A silly homebrew mount creature I'm working on for my homebrew campaign setting. First time I've made a creature, so I'd appreciate feedback. Also, any help determining CR would be appreciated.
If you didn't already gather from the name, this thing is a chameleon-kangaroo hybrid. Inspired by this.

Unseen Bounder (or the Chameleroo)
Size/Type: Large Magical Beast (Augmented Animal) (Mutant)
Hit Dice: 3d10+6 (22 hp)
Initiative: +1
Speed: 50
Armor Class: 14, touch 10, flat-footed 13 (-1 size, +1 dex, +4 natural)
Base Attack/Grapple: +3/+10
Attack: Bite +4 melee (1d6+2) or tongue +4 melee touch
Full Attack: Bite +4 melee (1d6+2)
Space/Reach: 10 ft./10 ft.
Special Attacks: Tongue
Special Qualities: Low-light vision, Darkvision 60 feet, Blend
Saves: Fort +5, Ref +4, Will +2
Abilities: Str 15, Dex 13, Con 15, Int 3, Wis 12, Cha 16
Skills: Jump +13, Hide +0
Feats: Endurance, Runner
Enviroment: Temperate plains
Organization: Domesticated
Challange Rating: 3

Special Attacks
Tongue: An unseen bounder's tongue is a primary attack with 15 feet reach. An unseen bounder's tongue deals no damage on a hit, but the target is automatically grappled by the unseen bounder on a hit. The unseen bounder can not deal damage by grabbing in this way, but it can make an opposed grapple check to pull the grappled gather 5 feet closer. An unseen bounder does not gain the grappled condition while using its tongue in this manner.

Special Qualities
Blend (Su): Three times per day, as a standard action, an unseen bounder can cause it's hide to take on the hue of it's surroundings for a number of rounds equal to its Hit Dice. This gives the unseen bounder a +6 circumstance bonus to Hide, and the ability to hide while being observed.
Domesticated: An unseen bounder is treated as an Animal for the purposes of Handle Animal and other skills.