Elgaud Shieldmate

Soulbond usually trades a body for an upgrade you both keep: two creatures share a keyword, and the value lies in stapling something like flying or lifelink onto a partner that lacked it. This one converts the mechanic's reciprocity into mutual insulation. As long as the pairing holds, both creatures gain hexproof, so the protection is a closed loop: the partner can't be targeted, and neither can the source granting it. That symmetry is what makes it more durable than a hexproof keyword printed on a single threat, since opponents can't peel the cheap half off to expose the valuable one. The whole bubble has to be answered without targeting it, which pushes them toward sweepers, edicts, and other untargeted removal. The constraint is the pairing's permanence working in the other direction: soulbond locks once it triggers and can't be voluntarily broken or reassigned, so the bubble lasts exactly as long as you control both halves and not a moment longer. Lose either creature to a board wipe or a sacrifice effect and the hexproof evaporates from the survivor too. The stats are incidental to the function; this is a creature whose job is to exist alongside something that matters and make the pair collectively immune to spot removal, with partner selection happening at the moment one of them enters rather than at any time you please.