Goblin siring is a bit murky to me
In particular, decisions around font face choices, card frame, and text and background colors can wait until your game is more mature
However, the fully stationed mode of The Seriema turns your legends that attack or want to tap for an ability into robust permanents for the small cost of seven charge counters
This is mostly to avoid the look of impropriety, as being able to see the back of the card means theres the possibility of marking (i.e., putting marks on certain cards so you can tell when they pop up in your deck without drawing/scrying them)
I see Sinkhole Surveyor as a beater that can get out of cheap removal range fast, and with some Bloomburrow bats around, the life loss is somewhat relevant
Search your library for a basic land card, put it onto the battlefield, then shuffle