Nova's Cactus Defenses is a cactus defense system made by Nova in The Ex-Communicated Series. The original idea of the cactus defenses is to have his/her property surrounded by cacti, in order to hopefully kill mobs as they run into the wall of cacti.
The system was introduced in the third season of the Ex-Communicated Series, as Nova was pondering on a solution to eliminate mobs from entering and destroying his property. He originally started with a few cacti in front of his house's entry way. After the progression and growth of the cacti, he started surrounding his house with cacti. The system became successful on a few mobs, such as a bear, which ran away after taking damage from the cacti.
Nova re-introduced the defenses in the fourth adventure of the Ex-Communicated Series. SSoHPKC became the first person to use the defenses during the series, as he put down cacti on the side of his house facing the desert, on 3 different levels of altitude. Nova used the idea again, as he surrounded his sandstone house with cacti. The system has not yet been completely successful, as a fire ogre has broken through the system.
The cactus defense returns to TreeTopia defending Nova's sand-based home in the desert in the second world.