Caboose is a quirky friend-to-all person who exhibits several personality quirks ranging from slightly insane to rather intelligent. He exhibits several vocal tics ranging from oversimplifying to over complicating statements. He is normally portrayed as a Blue and Black Toa wearing Nuva Armor, and wears a mask with a prominent visor and sun-blocky-thingy(Whatever it is that juts out over his eye/visor.) with the area that covers under his eyes sticks out a bit too, but much less so than the sun-blocky-thingy. In almost all recent renditions of him his visor does not show his eyes, rather it morphs and flexes to express feelings, resulting in a unique library of expressions. Caboose was created by, well, Caboose, as a internet avatar and representative of himself.
Brotherly Love Comics
In the series, Caboose was a general idiot and especially insane, with Zakattack playing the straight man, however, these two positions were often switched around. Other characters were pushed to the wayside.
Vaku's Comics 2.0-3.0
Caboose was generally enamored(Note this, not obsessed, enamored...) with Halo in this series, Caboose(Author) did not post enough to get featured heavily. During the Pirate storyline and on the unimaginatively named ship(The Red Pearl she be!), he lugged a cannon across the deck, and took a long time at it because said cannon was very heavy, he mistargeted and ended up hitting the opposing pirate's cannonball, he then engaged in boarding. Caboose also discovered Copy+Paste and shot up a GS due to identity confusion.
Caboose first landed on the beach after being thrown from the plane, completely dislocating his arm(Literally!). He then met Dr.Random, who planned to eat caboose's arm and prove his worth to the other survivors with him(Hapori Tohu and some orange and black guy.) Caboose soon talked him out of it and then left with him into the island, discovering they had left the others behind, Caboose admonished Dr. R's nonchalance towards the problem. Dr. R was soon whisked away back to where he started and left behind a disenchanted Caboose, who was then cheered up with the appearance of food in the form of mushrooms. More recently, he was shot by Plot Device. Wether he is dead or not remains to be seen.
Psycho Dogs and Carbonated Beverages
Caboose first appeared as a guest star on PDaCB, revealing a previously unknown and mutual hatred between he and Kiwi, who almost had attacked him with Kiwis(Bird) until T-E reminded him he only had power over the fruit. He was more often than not used in the co-author's comics, resulting in much insanity, including the selling of (Poor) Sheila the Tank, who had been later rebought at Ikea by Caboose. What relationship they have is unsure at best.
In Gilk, Caboose is a toa of iron who loves waffles and is quirky as can be, he is a much more consistent character, well, as consistent as Caboose gets, at least. His personality here is the same as the one described in the Personality section. In comics two, three, and four he is largely inactive, playing Halo in his helmet/mask. Then Caboose, after a long period of laziness and procrastination, was visited by choices, this visiting soon turned into threat-making, and so Caboose ran, running past Zakk in the process, relieving him of boredom. Eventually Caboose came to his senses/worked up enough courage, and challenged the existence of the voices, he ended up decapitated and his head mounted on a pole. For some reason or another he wasn't dead, merely disembodied, he was really snarky the whole time too, but wouldn't you be as well?
Caboose is primarily the same as he was in Gilk, now, though, he has a bit more backstory. Caboose is a OoMN agent stationed on one of the small islands off the southern end of Mata-Nui. Caboose is also one of the last few toa of iron, so he was stationed at this secluded area for his own safety, as the Makuta were actively hunting his kind down.
Caboose has a rather steady personality, in contrast to how he expresses himself,that is.