ok does an unmateable right before it leaves does it lay an egg with tarakotchi inside? becase my freind told me that. but i like tarakotchi so no worry if i get him
What do you mean by an "unmateable"? Do you mean an old character? If so, then no, it doesn't leave you an egg. To mate an oldie you have to connect with another oldie, as the matchmaker will not come. Your baby from the oldie will turn into an Oyajitchi after an hour; it skips the child and teen stages and goes right to an adult.
I should't listen to everything he/she says, no tama is un-mate-able even an oldie can mate, with another oldie of the opposite gender and only adult or oldies can mate. But i have heard of some teenagers mating! And when it leaves (passes away) then it will turn into a angel and you will have to start again by pressing A and C together, untila new egg appears. And an egg will not contain a Tarakotchi it will contain a baby boy (black) or a girl (white).