Remember the first time you saw a colossus? For me it was 20 September 2008. (ahhh,
long gone are the days of void friend lists and some dude named Keelen) I describe it like this:
"I go about my business of killing these fantastic hulk-looking rock golems when another necromancer joins the fight."
Nowadays I'm thinking new players first see the Colossus as pets on passersby in Wizard City Commons, and if not there, then certainly out in the Oasis where Al Saf'wan peddles his reagents.

ATTACK! There's the gals showing off their versions of the colossus. Saf'wan is our General leading us into battle. :-)
Let's review all of them:
1- Ice Colossus. Ahh, poor Myrna (my ice wizard) would love an ice colossus someday. It's the level 48 pet of our dear ice wizard friends. It comes complete with +5% power pip chance and a card of ice colossus. Maybe someday I'll have one of these.
2- Earth Walker. This here is every life wizard's dream pet as they are leveling up. Why? The 5-pip wonder spell for life wizards! Yup, it comes with 1 card of Earthwalker, which does 420-500 life damage. It's a little spendy at 10280 crowns . . . ok, it's A LOT spendy at 10280 crowns. You used to be able to buy this little guy for gold in Dragonspyre. In fact, that's how I got Amber's Earthwalker. I can't remember exactly how much gold it was, but I think I remember paying well over 50,000 gold for it. /shrug . . . been a long time ago. This thing actually is rumored to drop from Tumok (unlike the, uh, Skeletal Pirate pet hehe).
3- Magma Colossus. This here is the uber pvp pet for Warlords. yeah, I don't have one and even if I did, I don't think I could equip it. It's for Warlords only. This comes with the ever awesome +5% Power Pip chance AND a card of Pierce. I've only ever seen a handful of these, but that's probably because I don't spend much time in the arenas.

That is one nice looking colossus. *whistles*
4- Walmart Colossus! Now this colossus is so my speed! LOL! Colossusofwalmart.com yo. As you can tell from that picture above, I'm fond of the Walmart Colossus. haha! I've got a handful of these bad boys scattered across my characters. For ten bucks you get a cool colossusofwalmart.com pet AND crowns. YEAH! These all have varying effects, so you should always check the
gift card pet page so you know what kind of colossus you're getting.
So as you can see with that list above, getting your colossus will either take a trip to Walmart and ten bucks, obtaining level 48, farming it from Tumok (laf), obtaining warlord and spending 1500 tickets in pvp, or shelling out 10280 crowns. The colossus isn't the easiest pet in the world to obtain . . . imagine, enduring a Walmart trip . . . /shiver. Ahhhh, it's not so bad. :-)
Take your Colossus out of your bag and let 'em run around on those stumpy legs today because, whatever the flavor, today is the day of the Colossus pet!
Happy Dueling!