When a Spell/Trap Card, or monster effect, is activated while you control a "roid" Fusion Monster: Negate the activation, then send all cards with the same name as that card from the activating player's Deck and Extra Deck to the GY. You can banish this card from the GY, then target 1 "roid" monster in your GY; add it to your hand. You can only use this effect of "Emergeroid Call" once per turn.
How to Get
Negates any card effect activated.
Sends all other copies of the negated card from the deck to the graveyard.
Retrieves Roid monsters from your graveyard.
You must control a Roid fusion monster to activate this card.
Negating a card and sending all copies of it from the deck to the graveyard usually means that you wont be seeing your opponent use it for the rest of the duel. This is especially true for Spell/Trap cards if your opponent does not have any retrieval effects.
Be careful because sending cards from the deck to the graveyard could benefit your opponent especially if those cards can be retrieved or have floating effects.
If you negate a staple card and send only 1 to the graveyard, you can assume that the third copy is in your opponent's hand.
You can activate this card when you have a Roid Fusion monsters on the field. You can then banish Emergeroid Call from the graveyard to retrieve a Fusion material from the graveyard.
Roid Fusion monsters
Since you need a Roid fusion monster on the field to activate Emergeroid Call, here are some monsters you can have on the field. Elemental HERO - Necroid Shaman counts because it has "roid" in it's name even though he is not part of the Vehicroid archetype.