Explosive Singularity
Sorcery
As an additional cost to cast this spell, you may tap any number of untapped creatures you control. This spell costs 
less to cast for each creature tapped this way.
Explosive Singularity deals 10 damage to any target.
Liiga Smilshkalne
Kamigawa: Neon Dynasty (NEO)
• #140Rulings
Explosive Singularity's additional cost can't reduce its cost below {R}{R}. You can tap any number of untapped creatures, however, even if they won't reduce the cost further.
(wotc • 2022-02-18)
Rulings
Explosive Singularity's additional cost can't reduce its cost below {R}{R}. You can tap any number of untapped creatures, however, even if they won't reduce the cost further.
(wotc • 2022-02-18)