The tap effect runs afoul of the "fatty problem" where you don't want to use a tap ability on your fatty, you want to swing with it. However, this one has a built-in solution: get your [Radiation] from somewhere else.

This got used along with a couple of Beam-Focus Relic and some other Radiation source to deal 16 damage. It's pretty strong, but it is a rare Dragon-a-like. I don't yet think it's too strong, but I'll give it some more testing.

I really like this art. Did you really just add it? I feel like I've seen it before.

Would it just be better to have this card say "When ~ enters the battlefield, and at the beginning of your upkeep, you may sacrifice an artifact. If you do..."

@jmg: The times you want power effects aren't that predictable, though. Illumination Preacher in particular might want it at the start of combat or in the opponent's turn. (Must get around to reflavouring that guy.)

@Link: I did actually think I'd already given this art to something. But it's not anywhere in the visual spoiler.

I think the tap makes sense, in that it's always powerful, but REALLY powerful with another radiation source. Does it need sacrifice an artifact on the first ability as well?

Also, this doesn't matter much, but it'd be nice if the damage matched the P/T, although I realise that may not be balanceable.