Bash

Bash is a passive ability that gives a unit a chance to stun its target on attack. Most bashes also include some extra damage upon proc. This damage is usually directly added to the attacking unit's attack damage. If it is directly added to the attack damage, the unit can lifesteal off of it and it is affected by attack damage reduction. However, it cannot crit or cleave and is not affected by attack damage increasing effects. Illusions cannot bash.

Multiple sources of bash do not stack. Heroes with a bash ability can purchase items which provide a bash but are restricted from proccing it. The only exception here is the mini-bash from, which fully stacks with all other bashes, and even with multiple Monkey King Bars.

Other sources
The following abilities involve a bash mechanic, although they are not triggered as a chance on attack.