Trap Monster
Trap Monsters are a type of Continuous Trap Card that is Special Summoned as a Monster Card after it is activated.
TCG/OCG:
Anime Only:
All these cards are treated as both Monster Cards and Trap Cards while they are Summoned to the field, and as such, take up both a Monster Card Zone and a Spell & Trap Card Zone at the same time. If they are negated with "Jinzo" or "Royal Decree", they will return to the Spell & Trap Card Zone as Continuous Trap Cards with no effect, and will remain there even after "Jinzo" or "Royal Decree" are removed.
Trap Monsters are typically used as an emergency defense, to stonewall an opponent ("Metal Reflect Slime" is particularly useful in this regard), but they are also used to provide quick Tribute Fodder for higher-level monsters, such as the Monarchs, and can in some cases be used offensively as well. Also, because they don't count as monsters while in a players' Deck or Graveyard, some effects might work on them as a Trap Card, while others (like the effect of Morphing Jar #2) don't see them as a monster. This can be helpful in some cases.
Now that Synchro Monsters have made their debut, another use for Trap Monsters besides defense and Tribute Fodder for Tribute Summons is a method of getting enough monsters of a particular level on the field for a Synchro Summon. Since all Trap Monsters are Level 4 (with the exception of "Metal Reflect Slime", which is too high a level to be useful for a Synchron Summon), they can be used to quickly Synchro Summon a Level 5-8 monster.
"Imperial Custom" makes Continuous Trap Cards indestructible. If you control a copy of "Imperial Custom" and a Trap Monster, the Trap Monster will not be able to be destroyed by battle OR by a card effect. This combination is especially potent in defensive decks.
Trap Monsters may also be useful in a Uria deck as it will most likely need more monster support and these cards can not only provide it, but can be used as a Tribute to Summon "Uria, Lord of Searing Flames" as well as give him extra ATK points.
If "Book of Moon" is used against an already active Trap Monster, the Trap Monster is set as a Trap Card again and can be activated the next turn.
It is usually a good idea to have "Trap Eater" and "Double Snare" in the Side Deck of a deck using high concentrations of these cards, so that you are capable of destroying cards such as "Royal Decree" and "Jinzo" which would cause your Trap Monsters to become useless cards on the field. "Magic Planter can also work well in this case, as it allows you to draw 2 cards by sending a face-up Continuous Trap Card to the Graveyard.
