Reinforced Obsidian (Ender IO)

The Reinforced Obsidian is a block added by Ender IO. It has a blast resistance of 2000, making it "Wither Proof", as the tooltip notes.

Bugs
When looked upon through a Thaumometer or Lexica Botanica, the client will crash. To fix this, log in again and quickly switch to a different item in your hotbar before the chunk you're in loads. Some people report they had to downgrade FTB to be able to look away from the reinforced obsidan. This supposedly also happens if you middle-click the block in creative.