The Crested Old Man Opuntia is a fascinating cactus known for its fan-shaped growth and woolly white covering. This unique form comes from the standard columnar Opuntia vestita but develops crest-like ridges that look like waves or coral.

How to care for your Opuntia -

Water: Water sparingly and allow to dry out in between watering

Light: Prefers medium light conditions.

Humidity: Will thrive in average humidity levels

Temperature: Needs average to warm conditions 16-25°C but will be OK down to 10°C for short periods.

Other info - 

Toxic to cats & dogs? No but best to keep away from pets due to their small painful spikes.