From the verb: 'to blob.' It is the action of cancelling ones plans at the last minute, generally leaving the other people in the lurch.
Hey, Susan totally blobbed on our trip to the mall.
To be extremely drunk, heavily intoxicated, hammered, shitfaced, blitzed, inebriated, wasted, smashed, blasted, etc.
Jamal: hey, what are you doing tonight?
Ray: I'm going to the bar & getting completely blobbed.
Jamal: awesome, can I get blobbed with you?