ANT stands for Ad Nauseam-Tendrils and is a combo deck combining these two cards for lethal amounts of lifeloss to the opponent, popular around the time of Grand Prix Madrid 2010.
The player searches out the Ad Nauseam with Mystical Tutor or acquires the Ad Nauseam or the Tutor with various card-quality improving cards such as Brainstorm or Ponder. Getting the Ad Nauseam with Infernal Tutor while emptying the hand with Lion's Eye Diamond while Tutor is on the stack also works. The Ad Nauseam is then played, drawing a large number of cards with little lifeloss due to their relative cheapness. These cards are then played generating a large quantity of mana stringing together cards such as Lotus Petal, Dark Ritual and Cabal Ritual to play the Tendrils. If the Tendrils is not acquired from the Ad Nauseam, it can be gained with the aforementioned combination of Infernal Tutor and Lion's Eye Diamond. All previously played cards increase the Storm count for Tendrils.
Discard spells such as Duress and Thoughtseize are used to protect the combo from interference by the opponent.