Something in the game must tell you to roll a die. If you roll a die for any other reason (to simulate a coin flip, to choose pizza toppings, to create alternate timelines), that roll doesn't count.

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.

If a die is rerolled, the original roll essentially never happened: it doesn't cause any abilities to trigger, and no effect that cares about die rolls will consider it.

Results can be numbers not ordinarily possible on a six-sided die. Spells like Scooch can change the result to 0 or 7, for example.

The +1/+1 counters that are also Food tokens are still +1/+1 counters. They should stay on whatever permanent they were on, even though they become permanents themselves. That acorn symbol at the bottom of the card isn't messing around here.

Each die is identified by the number of faces it has. A six-sided die is a die with six equally likely outcomes: 1, 2, 3, 4, 5, and 6. The roll must be fair. Although physical dice are recommended, digital substitutes are allowed except in cases where the physical die is required for the effect.

The activated ability doesn't target any creature. You choose which creatures get counters after you roll the dice. If you roll two odd numbers, you may put both +1/+1 counters on the same creature.

The +1/+1 counters/Food tokens are artifacts, so anything that counts artifacts will count them. They can be tapped, untapped, sacrificed, and so on. They can even attack and block if you find a way to make them creatures.

If an ability triggers "whenever you roll a die," it will trigger whenever you roll any die, including the planar die. This is a change from previous Un- rules. Some abilities use the result to determine part of the effect. If you get a non-numerical result (currently just the planar die, but the future is long), that part of the effect won't do anything.

+1/+1 counters aren't "attached" to the creatures they're on like an Aura or Equipment is, so a +1/+1 counter/Food token that becomes a creature stays on the creature its on. It still gives that creature a +1/+1 bonus. It doesn't give itself a +1/+1 bonus. Note that +1/+1 counters/Food tokens don't have a mana cost, so their mana value is 0. Many ways of turning them into creatures will turn them into 0/0 creatures, so unless something else is raising their toughness, they'll immediately spoil . . . er, die.