Used in Spanglish (sometimes referred to as Pocho) this South Texas colloquial phrase describes a situation, person or group that is exceedingly difficult to deal with. Also, however not as often, the phrase can be used to describe something that looks cool or tough.
1) Dude, remember when you crashed your new truck into your house and ended up in the living room. Man that was gacho-bad.
2) Wow! That tatoo is gacho-bad!