All of the -1/-1 counters must be put on a single creature. You can't choose to split them up between multiple creatures.

If Boggart Mischief is put into a graveyard from the battlefield at the same time as one or more Goblin creatures you control die, its last ability will trigger for each of those Goblin creatures.

If a creature has +1/+1 counters and -1/-1 counters on it, state-based actions remove the same number of each so that it has only one kind of those counters on it. For example, if a creature has three +1/+1 counters on it and two -1/-1 counters are put on it, state-based actions will remove two of each of those kinds of counters, leaving the creature with just one +1/+1 counter.

While it appears only on cards that already have other card types, kindred is a card type and will be counted by effects that refer to the number of card types among cards in a zone.

The creature you choose to put -1/-1 counters on doesn't have to have enough toughness to survive the process. For example, if you blight 2, you can choose to put the counters on a 1/1 creature you control.

Once you've announced that you're casting a spell or activating an ability, players can't take actions until you've finished doing so. Notably, opponents can't try to destroy or otherwise remove your creatures to stop you from blighting as part of paying the cost of that spell or ability.

If you can't place -1/-1 counters on any creatures you control (probably because you control no creatures), you can't choose to blight.

If a creature that has +1/+1 counters on it receives enough -1/-1 counters to cause it to be destroyed by lethal damage or put into its owner's graveyard for having 0 or less toughness, effects that refer to the counters on that creature when it died will see all of those +1/+1 and -1/-1 counters.

Some older cards were originally printed with the "tribal" card type. That card type has been replaced with "kindred." This change does not affect the gameplay function of these cards.

Kindred is a card type that allows noncreature cards to have creature types. For example, Morcant's Eyes is an Elf (although not a creature) while on the battlefield and an Elf card (although not a creature card) in zones other than the battlefield.