Ice cap is a card with decent attack, and the ability charge. Usually used as a disposable card when wanting to quickly dispatch an enemy.
If you decide not to use its charge ability, it's not recommended to place Ice Cap by itself on the board against Justice, as its passive ability would typically kill Ice Cap. Particularly useful when wishing to surprise the enemy, typically either via dealing the necessary damage to defeat the opponent that turn, or by removing a taunt to use your other cards to attack. Because of this, users of Ice Cap should typically try to use it at the last optimum moment so that the opponent doesn't have time to change tactics, it also means that Ice Cap typically shouldn't be used to dispose of enemies that can be destroyed by other monsters with lower, or equal attack.