Realism:Use fist and smash into character head. Spontaneously.
Then, probably, being beaten by whole bar, or safely retreated if no further action taken (my character doesn't continue beating after taking action).
Against characters, who were godmodding against me earlier, possible godmodding with description of results of the hit without letting them decide/deflect it
Fantasy:Almost the same, but using a handgun as a knuckle to deal greater damage.
Then could start shooting people, if they would try to "blob"
Probably end getting shot as well.
What happened really in last rpCharacter simply caught the glass, put it on the table and continued conversation, because was trying to start a fight with someone else