ok humor me...wouldn't it make more sense if it is played with gravity pull (for the fact that it actually would have some kind of force 
) and give it like 30 hp or something, then have it blow up when it dies? a little more logical the poisoning an entire star
The poisoning concept was brought on by me, because there needed to be a 'limiting' factor to how the Red Giant was killed - otherwise, if it gets killed by ANYTHING (including gravity pull), it can trigger tons of explosions from multiple Red Giants on the field, thus causing a massive amount of damage in one turn. Yes, having it killed by 'Gravity Pull' would make more sense, but then again, the possibility of it triggering other 'Red Giants' upon its death would bring us back to the same problem/question I purposed earlier.
If you found a way to play the upgraded version two or three times and killed one with a Lightning Bolt, you would effectively deal 60 damage to the opponent that cannot be stopped, reflected, or otherwise negated. This is more potent than having to wait one turn to trigger an Unstable Gas after playing it, not to mention that Unstable Gas's effect can be reflected and 'controlled' by means of permanent control. Killing this creature would hurt you more than immortalizing it, similar to Voodoo.
cebra - here's a more accurate link of the image you provided (you can probably place this next to the other link you have for Sun if you really want):
Sun:
http://www.astronomyroadshow.com/Global.htm
EDIT: Dang, ninjaed by the author himself. 
Yeah it is, definitly.
But it´s easy to abuse.
If the effect is:
"If dies, deal 30 damage to opponent"
And it has like 30 HP, you can just use Immolation/Cremation to blow it up. That would be too easy. So you need to clarify how it has to die. Well, the only damaging effect that damages in more than one round is poison. So, the card is automatically poisoned, because I want it to lose it´s HP frequently.
it only deals 20 according to the card?
and to fix the cards chain reaction problem say: cannot be targeted by spells, only explodes when killed by a creatures attack, things along those lines
for the chain reaction, by the rules set now, only 1 creature can have gravity force on them so for coding reasons have it say only may play 1 red giant at a time, or have the gravity force switch around like it would in the game (ie you have 2 armagios, you use ability on one, almost dies, activate other amagio, only for this card, that switch happens when you play a new red giant)
if it has 30, there is virtually no way to set off all of them at once, especially if only one of them can have gravity pull on them (AI won't target the other cards if one is closer to death, and human players would be stupid enough to kill 6 of these on purpose)
as for the frequency of attacks, most deck will have some kind of muscle on them, so 1 turn of a dragons attack can take about the same amount off as 10 turns of poison, so if you do 30 hp, it will go in 3 turns with just that
