If a move's type is completely ineffective due to one of the opponent's types, then the move does zero damage, even if the opponent has a second type that would be vulnerable to it (as in Thunderbolt, an Electric-type move, used against a Quagsire, a Water/Ground Pokmon)
Theres a whole category of cards that just let players dump things into play, and my experience is that it rarely works out for the person casting the card that lets them do it
The OCG set includes 60 cards
Yes, Pokmon cards, especially the rare and expensive ones, have proven to be a good investment over the years
For four mana, Sakashima can enter the battlefield as a copy of any other creature its owner controls, and negates the "Legend Rule" as long as it's in play
destroy all monsters on the field with that Attribute, also until the end of the next turn, neither player can Special Summon monsters with that Attribute