!! does collapse all the rolls into just one. !10 rerolls and if every subsequent die is also a ten it rolls that as well. So if you roll 10, then 10, then 10, then 7 that would should up as all 4 dice, with a total 37. The !!20 method works differently because it only displays one die. If you roll 20 then 20, then 7, it will show a single die with a value of 47. In your case your d20 rolled a 10, which explodes and creates another roll, and that rolled a 20 then a 12, and since the 20 collapses rolls into one, you got a single die showing a value of 32. There are situations where the !10 will have the rerolls as separate dice. Like if you roll /roll 3d10!10>7 this will roll 3 d10, check if any are 10s, and and roll those into the pool and check them each against a target of 7. So if your rolled 7, 10, 5 you would get successes, and 1 extra die. if that extra die rolled 10, 7, you would get an extra 2 successes, but if the extra die rolled 3, you would get no extra sucesses buut you'd see dice output of 7, 10, 3, 5 (in that order I believe). If you tried that with the !! method: /roll 3d10!!10>7 you would never get any extra dice. If you rolled 7, 10, 5, and the exploding 10 rolled 10, then 7, it would be displayed as 7, 27, 5, and you'd get 2 successes. So each of these two exploding dice operators works differently. However you cannot use the same operator twice like this: /roll 1d20!!10!!20 /roll 1d20!10!20 If you try you'll just get an error. The torg sheet uses both operators (!10!!20) because its the only way to get a die to explode on both 10 and 20. We are lucky that roll20 provides these two different exploding methods, because without them both it would be impossible to do torg dice rolls.