In the latest “The Dragon War”, in the right hand node, it’s possible to use node effects to give your cards flash.
I’ve had multiple reports from my coalition that if you steal a creature with In Bolas Clutches with flash, then it joins your side, but still attacks you. I’ve just seen it myself stealing some zombie tokens from Nicol Bolas.
//Edited Title - Tombstone
Interesting. I’ll pass this along to the team for investigation.
I had something like this happen to me. I had used my Planeswalker’s ultimate ability, which gave the Flash ability to all the cards in my hand, including two copies of In Bolas’ Clutches. My opponent had a Spiritmonger in play. During their next attack phase, I used Clutches to steal the Spiritmonger, which proceeded to deal lethal damage to itself. My assumption is that the creature’s Berserker evergreen ability caused it to attack itself while it was changing ownership.