Aberrant Manawurm
From Secrets of Strixhaven set
Aberrant Manawurm
Creature — Wurm
2/5
Trample
Whenever you cast an instant or sorcery spell, this creature gets +X/+0 until end of turn, where X is the amount of mana spent to cast that spell.
Rulings
- Aberrant Manawurm's last ability resolves before the spell that caused it to trigger. It resolves even if that spell is countered or otherwise leaves the stack.