It's very wierdly worded and doesn't follow the conventions of the game. The text should be: "Play: I start a free attack challenging an enemy and strike a random different enemy"

As an instant effect this is very toxic and very high variance since it's basically start a free attack and kill a random enemy at burst speed. Making it a skill would make this a bit better, but the card doesn't really fit anywhere. Control would rarely want to run it because they have no use for an 8/5 overwhelm body and it's not necessarily a finisher, and aggro will never run an 8 drop (except maybe Farron now that decimate is rotated), midrange noxus maybe likes this but it likely dies on the attack so it's also kinda shit in midrange.

Either way random kill/strike effects should be rare if present at all and definitely shouldn't happen at unit speed