Mana screw

Mana screw (Referred to as being Mana hosed by Wizards of the Coast ) is a term that refers to the condition of either not having enough mana or not having the right color of mana to play the spells in your hand. Mana screw can be the result of several factors: poor luck; an opponent playing a strategy to reduce your mana (such as land destruction and other forms of mana denial); or poor deckbuilding. The lattermost factor can be due to too few lands (or other mana sources), improper colour ratio, or a combination.

The joke set Unhinged has a card called Mana Screw which satires the random nature of mana screw by providing mana at random. The illustration depicts an actual screw.

Color screw
Color Screw refers to a specific type of mana screw, where a player, while perhaps having plenty of mana/acceleration, lacks the correct color to play certain spells. e.g. A player may have six Mountains, but lacks the Swamp they need to cast a Wrecking Ball.