Disadvantage

Disadvantage is a term for when you lose advantage over your opponent.

Details
Evolution Creatures are often infrequently used due to their requirements of an Evolution Source, and loss of advantage when removed by a single removal card, causing a 2:1 advantage for your opponent (1 card used, for your 2 creature cards). This is especially true for Vortex evolution that require multiple creatures.
 * However, this was later lessened by evolution creatures with powerful Come Into Play abilities that provided other advantage, as well as being able to be put into the battle zone For No Cost, due to the Invasion ability.