[brad the fish]

Once he raised to 300, your raise to 890 made it so that he has 590 to call to win 1290 so he has 2 to 1 odds. If he folds he's at 2005 chips which is a shorter stack in relation to the table, however if he calls and looses hes at 1400 chips which is still playable - especially with another shortish stack in the BB when he's on the button. If he calls and wins he's at ~3400 in chips and becomes a very potent force at the table.

I'm not saying it's a good call on his part but I can see why he did it - ESPECIALLY if he thought you might do something like this.

In the future, in order to try this you really need more chips so that he's really hurting if he calls and loses.