Mammillaria nejapensis “Silver Arrows”
https://shopaltmanplants.com/products/mammillaria-nejapensis-silver-arrowsr/IndoorGarden - My new desk buddy! A Silver Arrows Cactus from Lowe's in a Bulbasaur planter from eBay.
https://www.reddit.com/r/IndoorGarden/comments/aba0vy/my_new_desk_buddy_a_silver_arrows_cactus_from/