Enchant creature When Grim Reaper's Sprint enters the battlefield, untap each creature you control
Blue bounce spells are the second best tempo cards in limited behind pure removal spells, so a reusable enchantment Unsummon dependent upon playing creature to begin with seems like a card that you'd like to have in your deck
Again, imagine cutting a card from Caleb Griffins deck: Creatures (14) Lands (19) Spells (27) Quite literally any cut we make in the deck (except for land) is going to move us closer to a 0 on The Burnsey Scale in a deck that isnt at all equipped to take advantage of the resilience and power of a Tarmogoyf
New Keyword Action: Earthbend Earthbenders use the land itself to build formidable attacks and fortify their position
Once you choose to do so, the ability will no longer trigger for the rest of the turn and any other instances of the ability that have already triggered and are on the stack won't have any effect
If you're selling CGC-graded cards, we'd lean toward Misprint or eBay over TCGPlayer