This card can be used as a suicide attacker, a Fusion Material, Tribute, or Stall monster. This card can give room for other monsters to attack. Your opponent might be cautious to destroy this card while your LP is higher. Using cards that change other monster's Attributes can be helpful. "Elemental HERO Divine Neos" can benefit on the effect of "Absolute Zero" for 1 turn only.
"Star Boy" will give an ATK boost from both its own effect and this card's effect.
Normal Summon "Deep Sea Diva" and Summon another with its effect to give this card an additional 1000 ATK.
Since most WATER monsters are also Fish, Sea Serpent or Aqua-Type monsters, this card's ATK can further be increased by Special Summoning the Fusion Material used to Fusion Summon it.
Some ideas include "Surface" (provided the Fusion Material was less than Level 3, and is in the Graveyard) and "Call of the Atlanteans" (if the Fusion Material was a Sea Serpent-Type, and if there are at least 2 other Sea Serpents in the Graveyard). "Call of the Atlanteans" is preferred since it can Summon 3 monsters, while "Surface" can only Summon 1.
Using the Destruction Effect of Absolute Zero
Use "Mask Change" or "Form Change" on this card to Special Summon "Masked HERO Acid". This card's effect will destroy all of your opponent's monsters, while "Acid" will destroy all of their Spell and Trap Cards. This is a great, simple combo that can clear the field to finish the game.
Activate "De-Fusion" to destroy your opponent's monsters, allowing direct attacks from your Fusion Materials
Fusion Summon "Elemental HERO Terra Firma" with "Polymerization", and then use "Miracle Fusion" to Fusion Summon this card using the same Fusion Materials. Then, activate the effect of "Terra Firma", Tributing this card.
If a combination of "Fusion Gate" and "Chain Material" are used to Summon multiple Fusion Monsters for "Catapult Turtle" to launch at your opponent, this card makes an excellent choice to add in. "Elemental HERO" Fusions and copies of "Catapult Turtle" not being used work perfectly as Fusion Materials for this card, and once this card is Tributed, its effect will activate and destroy your opponent's monsters.
Tribute this card for "Mobius the Frost Monarch" to destroy all your opponent's monsters and up to 2 cards in their backrow. "Mobius" can also be used as a Fusion Material for this card later.
Use "Advance Draw" to draw 2 cards and destroy all of your opponent's monsters.
Use with "Spiritual Water Art - Aoi" if this card is going to be destroyed, or if your opponent has a lot of monsters on their field. Then their field can be blow up and discard one card from their hand.
Countering Absolute Zero
If "The End of Anubis" is no your field when this card is sent to the Graveyard, "The End of Anubis" will negate its effect.
When this card's effect activates when there are at least 2 monsters on your field, activate "Starlight Road" to negate the effect and Special Summon a "Stardust Dragon".
A combination of "Book of Moon" and "Compulsory Evacuation Device" can be used to remove this card from the field without triggering its effect. First use "Book of Moon" to flip this card face-down and then use "Compulsory Evacuation Device" to return it to the Extra Deck.
If this card is going to be destroyed and send to the Graveyard, activate the effect of "Abyss Dweller" beforehand.
If "Future Fusion" was used to Fusion Summon this card, use "Giant Trunade" to return it to the hand and destroy this card, and possibly use "Future Fusion" again, or "Miracle Fusion" for another copy of this card.