Thing in the Ice // Awoken Horror (SIR-095) - Shadows over Innistrad Remastered

Defender
This creature enters with four ice counters on it.
Whenever you cast an instant or sorcery spell, remove an ice counter from this creature. Then if it has no ice counters on it, transform it.

When this creature transforms into Awoken Horror, return all non-Horror creatures to their owners' hands.