

If the team needs avoid a big threath Cocoon is a perfect choice, sometimes u can use it over a support to do a fast kill over the threath(assasins usually), otherwise u can use it over the threath and focus the support. The most dangerous are Zeratul with Blink so here you have to use it in front of the wall.

If u are facing a stealth enemy, remenber to use Toxic Nest near you to reveal it and so the tower help u to survive. If ur team lack CC u can use it over a Tank (Muradin, Tyrael, Anub.), you're going to tank and annoy the enemy! but usually you will need dmg to burst one or two annoying enemy assasins, so use it over a hero that u KMOW HOW TO USE IT, the best choice always assasins > specialist.

The ultimate choice depends of u, both are viables but if u know how to play with the heroes of your team Ultimate Evolution can be awesome if u use it over a good hero and it depends on what u need.
