Set this card and protect it, then on your next turn special summon "Lava Golem" to your opponent's side and then flip and activate "Jowls of Dark Demise's" effect to take control of it. Then you can make a direct with "Lava Golem" for a whopping 3000 points of damage, then when it's your opponent's turn again, they will take another 1000 points of damage.
You can then set a "Magic Cylinder" and when your opponent attempts to attack your vulnerable "Jowls of Dark Demise" with "Lava Golem", you do yet another 3000 points of damage to your opponent.
This is a great Side Deck card for the Gladiator Beast mirror match. If they attack into it with their Gladiator Beast, you can take control of it and tag it out for your own Gladiator Beast, since it has "attacked this turn".
Use this card in conjunction with "Book of Moon" in order to take control of 2 of your opponent's monsters.
If you manage to Flip Summon this card, use this card's effect to take control of a strong monster and Tribute it and this card to Summon a level 7+ monster.
You can combo this card with "Mask Change II" on your opponent's turn to send the monster to the Graveyard and bring out a Masked Hero card in its stead.
With "Ultimate Offering" in play you can set this card at the end of your opponent's battle phase so that it can then be flipped at the start of your turn. Skipping the danger of having it on the field for a turn. Also if it gets flipped in the middle of battle you can also use Offering to tribute the monster you just took control of for a lv 5 or 6 monster.