Oh snap!

[Couch Potatoe]

1)A term that seconds the taunting, comeback, and/or verbal abuse of another person.

[Tina]

An expression meaning that one has been surprised by what has just occured. It is similar to saying wow or holy crap but implies a more laid back manner.

[Zipporah Schumaker]

Something quickly catches your attention, startling, close call, also could be Oh Snaps