Green is the color of life, instinct, nature, reality, evolution, ecology and interdependence. Green has a large number of creatures, which tend to be the largest in the game for their cost. Many of its spells make them stronger temporarily. It can also destroy "unnatural" artifacts and enchantments, increase a player's life total, get extra lands or other mana sources into play, and produce the other four colors of mana. Green creatures often have "Trample", an ability which lets them deal attack damage to an opponent if blocked by a weaker creature. Green's weaknesses include its difficulty destroying creatures directly; a distinct shortage of flying creatures (though some of its creatures have "Reach", making them able to block flying creatures); and a lack of strategic options other than its signature large creatures.