Cohort

Cohort is an ability word introduced in Oath of the Gatewatch and associated with Allies. The activated ability requires tapping the Ally creature and another Ally.
==Description==
The cost of each cohort ability (tapping itself and tapping another Ally) is always the same but the effects differ wildly. While the costs could include mana, none do so, and all Cohort abilities are on Ally creatures. Because the cost includes , the Ally that has the cohort ability has to have been under your control since your most recent turn began. It can't have "summoning sickness." But the other Ally, the "an untapped Ally you control," could be one you just cast. 
Cohort was the lowest rated mechanic in the modern era, from the gameplay problems of being slow, weak and parasitic to the design problems of repetitiveness, narrowness and being game-slowing. The Storm Scale puts it at 8, avoiding a higher grade due to being hard to break and is creature-focused.
==Rulings==
* To activate a cohort ability, the Ally with that ability must have been under your control continuously since the beginning of your most recent turn. Informally, it can’t have “summoning sickness.” However, the other Ally you tap can be one that just came under your control. (Note that tapping the second Ally doesn’t use [the tap symbol].)
==Examples==
==References==