Loyal Mastiff

When Loyal Mastiff enters the battlefield, you
may attach it to a creature.
Loyal companion (While Loyal Mastiff is attached
to a creature, the creature gets +0/+2 and all spells or abilities that would affect it affect Loyal Mastiff
instead. If Loyal Mastiff dies while attached to a creature, you may pay {3}. If you do, then you may
play Loyal Mastiff attached to that creature as an
instant.)