Reasonable Side Effect?

[JmOz]

Side Effect: Whenever character takes body while using Power A Power B goes off (Power B is a No range explosion Attack that the character does NOT have PI to)

And if so what power should get it?

[Tom McCarthy]

You mean what SFX justify such a side effect ?

A big ole fuel tank on a flamethrower might do it. I think Blowtorch took a susceptibility to taking BODY to his fuel tank.

A complex energy field/energy gate might do it. If the character needs to carefully open a gate or energy field to cause an effect, and is disturbed, that might apply. For example, Firestorm the Nuclear Man could create a small fission or fusion reaction in the palm of his hand and shut it down before it did much more than an EMP. If he got smacked while doing so, I could easily justify a no range RKA explosion with no personal immunity.

As to the commonality of such an event (taking BODY while using a power), it depends on your defences compared to the campaign's average attack, your DCV, how frequently the power is used, and whether the power is constant or continuing or instant.

[JmOz]

Actualy got the F/X already, it is a warhead that while in flight if the attack is targeted it goes off prematurly

the attack in question is way over the setting max (it is a 7d6 KA with Explosion and AP) but the character has no imunity (and in truth will be at neg body from an average attack)