Taco Terror is a perk in Tower of Guns, unlocked after you have leveled your gun up a total of 70 times.
"Allow Gun Level 6"
If you often find yourself wanting more firepower, and think you have the ability to get it, Taco Terror is the perk for you. Trading off more specific benefits of other perks, a Level 6 weapon of any kind is a force to be reckoned with, if you can gather and maintain enough blue XP to keep it. However, if you need anything else, this perk may be replaced with one that does the intended job. It's a great go-to perk when you don't really care what perk you take, but it can make or break a run in the end.