Each half is an instant, and note that fuse at the end to cast them both
As a bonus, Enduring Vitality itself can chump block in combat, die to a board wipe effect, or even be sacrificed without losing its effect, since it comes back as an enchantment
You can set this up in the first few turns with Queen first, Nick Wilde Sly Fox Sleuth and the Queen damage ability on turn two, into Pluto turn three to play Queen again, setting you up for something similar turn four
But Loam does stand a head above the rest in terms of versatility and utility across different archetypes, not least because its the easiest to get back into your graveyard each turn without a discard or sacrifice outlet
A tapped creature is very unlikely to be damaged by anything, so this looks very close to a 1-mana Claustrophobia
This is great for you to build your win condition around specific Slivers