Clay Golem

Dice used must have equally likely outcomes and the roll must be fair. Although physical dice are recommended, digital substitutes are allowed, provided they have the same number of equally likely outcomes as specified in the original roll instruction.

An ability that tells you to roll a die will also specify what to do with the result of that roll. Most often, this is in the form of a “results table” in the card text.

You can activate Clay Golem's first ability even after it has become monstrous. It won't become monstrous again and you won't put any counters on it, but you will roll a die to activate the ability, which may cause abilities of other permanents to trigger.

Tournament events have more specific rules regarding dice and die-rolling. For more information, please see the most recent version of the Magic Tournament Rules at https://wpn.wizards.com/en/document/magic-gathering-tournament-rules.

The instruction to roll a die and the effect that occurs because of the result are all part of the same ability. Players do not get the chance to respond to the ability after knowing the result of the roll.

Some effects may modify the result of a die roll. This may be part of the instruction to roll a die or it may come from other cards. Anything that references the “result” of a die roll is looking for the result after these modifications. Anything that is looking for the “natural result” is looking for the number shown on the face of the die before these modifications.