Jump-start appears on some instants and sorceries. It represents two static abilities: one that functions while the card is in a player’s graveyard and another that functions while the card is on the stack. “Jump-start” means “You may cast this card from your graveyard if the resulting spell is an instant or sorcery spell by discarding a card as an additional cost to cast it” and “If this spell was cast using its jump-start ability, exile this card instead of putting it anywhere else any time it would leave the stack.” Casting a spell using its jump-start ability follows the rules for paying additional costs in rules 601.2b and 601.2f–h.
May 3, 2019 · War of the Spark
Mentor is a triggered ability. “Mentor” means “Whenever this creature attacks, put a +1/+1 counter on target attacking creature with power less than this creature’s power.”
January 25, 2019 · Ravnica Allegiance
Mentor is a triggered ability. "Mentor" means "Whenever this creature attacks, put a +1/+1 counter on target attacking creature with power less than this creature's power."
October 5, 2018 · Guilds of Ravnica
Mentor is a triggered ability. “Mentor” means “Whenever this creature attacks, put a +1/+1 counter on target attacking creature with power less than this creature’s power.”