help with a mob that has multiple abilities.

I am trying to make a mob that has multiple abilities, when a tick happens a procedure would run and select a random ability to execute. The first one would place blocks around the mob protecting it from players, and the second would be a projectile and ice particles would shoot at players. With the knowledge i possess right now i am not able to make the procedure know the X, Y, Z coordinates of the mob. If anyone could help that would be great.