Some kind of respawn ^_^ ?

Well hello !

I wanted to make some small side monster in my rpg [as soon as my rpg maker is fixed]
But how to make some kind of event that:

1ST: Monster battle
2ND: Monster dies and vanished
3TH: After a short time [10-20 secs or something like that] it respawns and goes the same way o.O

And could somewhone post my some kind of Star Ocean-like limit break gauge ???

Thank you,
Reamon