Whenever this creature attacks, you may
collect evidenceTo “collect evidence N” means to exile any number of cards from your graveyard with total mana value N or greater.
If a player is given the choice to collect evidence but is unable to exile cards with total mana value N or greater from their graveyard (usually because there aren’t enough cards to do so) they can’t choose to collect evidence.
A spell that has an ability that allows a player to collect evidence as an additional cost to cast it may have another ability that refers to whether evidence was collected. These abilities are linked. See rule 607, “Linked Abilities.” (CR 701.59) 3. When you do, 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 you control. (To
collect evidenceTo “collect evidence N” means to exile any number of cards from your graveyard with total mana value N or greater.
If a player is given the choice to collect evidence but is unable to exile cards with total mana value N or greater from their graveyard (usually because there aren’t enough cards to do so) they can’t choose to collect evidence.
A spell that has an ability that allows a player to collect evidence as an additional cost to cast it may have another ability that refers to whether evidence was collected. These abilities are linked. See rule 607, “Linked Abilities.” (CR 701.59) 3,
exileTo exile an object, move it to the exile zone from wherever it is. See rule 406, “Exile.” (CR 701.13) cards with total mana value 3 or greater from your graveyard.)