BackupBackup is a triggered ability. “Backup N” means “When this creature enters, put N +1/+1 counters on target creature. If that’s another creature, it also gains the non-backup abilities of this creature printed below this one until end of turn.” Cards with backup have one or more abilities printed after the backup ability. (Some cards with backup also have abilities printed before the backup ability.)
If a permanent enters the battlefield as a copy of a permanent with a backup ability or a token is created that is a copy of that permanent, the order of abilities printed on it is maintained.
Only abilities printed on the object with backup are granted by its backup ability. Any abilities gained by a permanent, whether due to a copy effect, an effect that grants an ability to a permanent, or an effect that creates a token with certain abilities, are not granted by a backup ability.
The abilities that a backup ability grants are determined as the ability is put on the stack. They won’t change if the permanent with backup loses any abilities after the ability is put on the stack but before it resolves. (CR 702.165) 1 (When this creature enters, put a +1/+1
counterTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) on target creature. If that's another creature, it gains the following ability until end of turn.)
Whenever this creature attacks, for each attacking
modifiedHas a counter, is equipped, or is enchanted by a same-controller Aura. (CR 700.9) creature you control,
createTo create one or more tokens with certain characteristics, put the specified number of tokens with the specified characteristics onto the battlefield.
If a replacement effect applies to a token being created, that effect applies before considering any continuous effects that will modify the characteristics of that token. If a replacement effect applies to a token entering the battlefield, that effect applies after considering any continuous effects that will modify the characteristics of that token.
Previously, an effect that created tokens instructed a player to “put [those tokens] onto the battlefield.” Cards that were printed with that text have received errata in the Oracle card reference so they now “create” those tokens. (CR 701.7) a tapped and attacking token that's a copy of that creature.
ExileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) those tokens at end of combat. (Equipment, Auras you control, and
countersTo counter a spell or ability is to cancel it: remove it from the stack without resolving it. A counter on an object or player is instead a marker that changes characteristics or interacts with rules or abilities; for example, a +1/+1 counter modifies a creature’s power and toughness. (CR 701.6; 122.1) are modifications.)