→Biology: We generally tend to not make comparisons from its evolutionary relatives
When Slowbro Mega Evolves, it becomes engulfed by the Shellder so that only its head, arms, and white-tipped tail are visible. Its head pokes out of the mouth of the Shellder and is surrounded by Shellder's now larger teeth. The spiral Shellder now has an opening at its tip, allowing the tail of Slowbro to stick out. Mega Slowbro balances on its tail due to its legs being engulfed. It can move by bouncing, using its tail as a spring. The spikes on the Shellder are now reduced to four on the bottom section of its body and the dark spots only visible on its middle section. Mega Slowbro's energy has gathered into Shellder, which has increased its hardness. This allows it to act as an armor so hard that nothing can scratch it. Slowpoke is virtually unchanged, but it gains some power and motivation from Shellder's digestive fluids.
Not much is known about Galarian Slowbro, but it does not have a Shellder on its tail.
Like it's pre-evolution, it has gained a slight color difference with purple spots on its forehead and belly. Its paws are also purple.
==In the anime==