The following rulings apply to all "Malefic" monsters.

OCG Rulings

• You cannot Special Summon a Synchro Monster if it was not properly Synchro Summoned previously, such as if it was removed from play directly from the Extra Deck. Thus, you cannot use an effect like "D.D.R. - Different Dimension Reincarnation" or "Return from the Different Dimension" to Special Summon a "Stardust Dragon" which was removed from play to Special Summon "Malefic Stardust Dragon". Also, "Blue-Eyes White Dragon" and "Red-Eyes B. Dragon" are Normal Summon monsters, so they may be Special Summoned even if they are removed from play directly from the Deck.^[1]

• If the effect of a monster like "[[:]]" or "[[:]]" or "Malefic Stardust Dragon" is negated by an effect like "Skill Drain" or "Forbidden Chalice", then its effect which prevents your other monsters from attacking is also negated, so you can attack with a monster other than "[[:]]".^[2]

• If the effect of a monster like "[[:]]" or "[[:]]" or "Malefic Stardust Dragon" is negated by an effect like "Skill Drain" or "Forbidden Chalice", then its effect "If there is no face-up Field Spell Card on the field, destroy this card." is also negated. Thus, "[[:]]" won't be destroyed if the Field Spell Card is removed from being face-up on the field.^[3]
• If "Skill Drain" is negating the effect "There can only be 1 face-up "Malefic" monster on the field." of a monster like "[[:]]" or "[[:]]" or "Malefic Stardust Dragon", then you still cannot Special Summon a second "[[:]]", since its effect is still active while it is in the hand.^[4]

• Suppose you control a face-up monster like "[[:]]" or "[[:]]" or "Malefic Stardust Dragon". If you control a Field Spell Card and activate a new one, then "[[:]]" is destroyed at the same time that the previous Field Spell Card is destroyed. However, if you control a Field Spell Card and your opponent activates a new one, then "[[:]]" is not destroyed since there is always a Field Spell Card on the field.^[5]

• Suppose you control a face-up monster like "[[:]]" or "[[:]]" or "Malefic Stardust Dragon" and another such monster which is face-down. If the face-down monster is flipped by an attack, then the flipped monster is destroyed after damage calculation by the effect of "[[:]]".^[6]

• Suppose you remove from play "[[:]]" with a card like "Interdimensional Matter Transporter", and then Summon another "[[:]]", all while "Skill Drain" is active. During the End Phase, even though the effect "There can only be 1 face-up "Malefic" monster on the field." of the "[[:]]" on the field is negated, that effect of the removed-from-play "[[:]]" is still active, so the removed-from-play "[[:]]" cannot return to the field. Thus, the removed-from-play "[[:]]" is sent to the Graveyard.^[7]

References

1. ↑ Konami FAQ: Can "D.D.R. - Different Dimension Reincarnation" Special Summon a "Stardust Dragon" which was removed from play to Summon "Malefic Stardust Dragon"?
2. ↑ Konami FAQ: If the effect of "" is negated, then can other monsters attack?
3. ↑ Konami FAQ: If the effect of "" is negated, then is it destroyed by its own effect if there is no longer a Field Card?
4. ↑ Konami FAQ: Can you Special Summon a second "" while the effect of "Skill Drain" is active?
5. ↑ Konami FAQ: Will "" be destroyed if a second Field Spell is activated?
6. ↑ Konami FAQ: If a battling "" is flipped by battle while there is no Field Spell active ^[sic], then when is it sent to the Graveyard?
7. ↑ Konami FAQ: Can a second "" return to the field by the effect of "Interdimensional Matter Transporter"?