Skemfar Elderhall
Land
This land enters tapped.
: Add 
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, , Sacrifice this land: Up to one target creature you don't control gets -2/-2 until end of turn. Create two 1/1 green Elf Warrior creature tokens. Activate only as a sorcery.
Johannes Voss
Kaldheim (KHM)
• #268Rulings
If you activate the last ability without choosing a target, you just create Elf Warrior tokens as the ability resolves. However, if you do choose a target, and that creature is an illegal target as the ability tries to resolve, the ability won’t resolve and none of its effects will happen. In that case, you won’t create Elf Warrior tokens.
(wotc • 2021-02-05)
Rulings
If you activate the last ability without choosing a target, you just create Elf Warrior tokens as the ability resolves. However, if you do choose a target, and that creature is an illegal target as the ability tries to resolve, the ability won’t resolve and none of its effects will happen. In that case, you won’t create Elf Warrior tokens.
(wotc • 2021-02-05)