Wards

Summons are a type of units that are created with spells. Players do not encounter them, unless they play as, with or against certain heroes. Summons are usually under the control of the summoning unit's player, but most of them can be converted by the enemy. Only very few of them cannot be controlled. Summoned units usually live only for a certain amount of time (although some stay permanently, until killed) after being summoned and a player can have a limited amount of summons.