darkSpyro

Since I've finished the game, and got most of the characters on lv 10 all upgrades, I decided to play around with their attacks, and this is what I found:

Warnado-EotS: If you hold down the A button (on Wii) to do your spin attack, after you finish, you stay in your shell until you let go.

Ghost Roaster-Any: If you charge just before a video scene (like the beginning of a boss battle) then you appear invisible during that video. It also works if you defeat someone with the charge in PvP.

Prism Break-Any: If you drop your shards in certain places in the game, they do not drop, but he still roars as if he has dropped them, making him look as if he is shouting.

Hex-Any: If you summon the bone wall on a bridge, or half off a cliff, you can see the other end of the bone in the ground.

Please post if you find any more.

Ghost-Roaster - Any: While charging, talk to someone. He'll continue to move forward, but won't be in the skull.
While like this, he can still kill enemies, like he's still doing the charge.

Hex - Any- Once you start a new game go to one of the walls with another player (with any skylander) who stands next to the wall. Now P1 take HEX back a little and summon her skull wall lifting P2
P2 walk up and over the wood wall . Your now in a locked area. P1 take of Hex and put her back on. Now both P1 and P2 are over the wood wall. You are in an area your not supposed to be in yet. HOORAY for U