Gateway Sneak lets you draw a card when you deal damage to a player with it, which is a solid ability
As far as making these big cull choices it is all about how much play a card gets
Looks quite harmless, but theres an immediately noticeable catch
(2025-06-06) In the incredibly rare case where, during your cleanup step, Ancient Adamantoise is phased out with damage marked on it, Ancient Adamantoise's second ability won't apply and all marked damage will be removed from it during that cleanup step
If Purphoros is attacking or blocking and it stops being a creature (probably because your devotion to red was reduced), it will be removed from combat
As a result, knowledge of Magic: the Gatherings color pie helps simplify understanding of Specialized creatures abilities