Summons

Summons are a type of unit that are created with spells. Players will 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 some summons.

There are 3 types of summons: Regular summons, which are treated like regular creeps by spells, usually have no active abilities and usually are not a big threat, Creep-Heroes, which are treated like heroes by most spells and are significantly stronger than other summons, and wards, which usually are immobile and fully immune to most spells.

Regular Summons
These summons are comparable to lane and neutral creeps when it comes to their power. A single one of them is usually not a threat, however, they can get quite dangerous when encountered in groups. Summons usually have certain abilities, which gives each of them a different roll. They can either be passive and used for scouting, or agressive used in fights. Losing regular summons is usually not a big deal, since they provide rather low bounties, they expire and they can be resummoned after a short while. Regular summons are treated like lane and neutral creeps by every spell.

Creep-Heroes
These summons are special in a way that they are treated as heroes by most (but not all) things. They are more powerful than other summons and usually the "main weapon" of the heroes which summon them. They usually do not come in groups, but are rather strong individual units. However, as a downside, their bounty is usually quite high and the spell they are summoned with have large cooldowns, so it is important for the player to keep them alive as long as possible.