Very straight-forward. The Spirit Bear cannot be affected by the Cripple of Lycan's wolves. It is the only non-building, non-ward unit which is immune to it.

1. Pick Lycan and level up Summon Wolves
2. Summon the wolves
3. Attack an enemy Spirit Bear
4. Observe its status bar

Result: Cripple does not proc at all.

Expected: Cripple should work against the spirit bear normally.