Base Smash Up
Dinosaurs, Aliens, Superheroes, Geeks
This is the only base with no ability, yet it has the clearly defined ability to deny your opponents victory points and clearly frustrate them if this base is used properly.
The Dinosaurs have the ability to break this base in a single turn, by themselves, using only two cards, with no preconditions. King Rex for seven power and a Rampage to reduce the breakpoint by that power will yield 2 VP, a very efficient tradeoff, particularly when another opponent started to play minions there, in which Rampage can be substituted for Augmentation or Upgrade.
This is one of the best bases to use with Terraforming. If you have an advantage over your opponents (or an extra minion play puts you into the lead), and there are a lot of minions on a base, you can waste all their effort and deny them any points. Aliens can also return minions to their owners hands as a stall tactic.
An easy Superhero combo with this base is to have The Burst on another base with a Mild Mannered Citizen on Jungle Oasis. The MMC can become Captain Amazing, which moves the Burst over to the base, and Captain Amazing's Talent adds the final two power in order to break this base. Captain Amazing herself with her talent and her action can also drop eight power, enough to blindside a careless opponent.
Watch out for the Geeks: Wil Wheaton, Felicia Day and Control Minion can steal this base in a hurry.