Tally is romantic pairing of Tad and Kelly.
They are often seeing breaking up and getting back together again throughout Seasons 1-2. In Season 3, Kelly breaks up with Tad, but Tad is seen to never move out of her hair. In “Conquer”, Kelly is fed up with Tad still living in her hair, and they have a brief argument. Tad then recites a love poem dedicated to Kelly before her soul is sucked away by Meteora.
Canon Probability Edit
Although they have an on and off relationship, Kelly and Ted may get back together because of the long realtionship they had before since Season 2, though it's not as likely as it used to be, due to her refusing to get back together with him several times (Lava Lake Beach and Conquer, notably) after her last break-up with him, which she said was for good. Kellco may also stand in the way of them being together, if Marco and Kelly start a relationship.