When you create tokens of the two creatures (which would require 7 total mana for the activation), the Peregrine Drake token allows you to untap five lands while the Corridor Monitor copy untaps Soul Foundry to keep making more tokens
The Sacred Cards"
Master Duel 2022-01-19 " Limit Code " pages Anime Yu-Gi-Oh
Steamflogger Boss: Part of a comedic incident in the "Unstable" set, this creature gives the player the chance to assemble Contraptions, even though no such mechanic officially exists
Throne of Eldraine Planeswalker Deck: Oko $44.99 US Shipping Only Due to export restrictions, this item may only be shipped to addresses in the United States, APO/FPO addresses, and Puerto Rico
The price you pay for the resulting effects would be very expensive if attached to an instant or sorcery spell, but seeing that they are attached to a creature and can be activated repeatedly and at instant speed, the additional price seems a bit fairer