Linus cannot regenerate irreplaceable body parts like eyes or limbs. He needs to reattach them physically.
Electricity or Intense Energy can disrupt his body in any form.
Backstory:
Linus was a kidnapped test subject to create an elite Technological Superhuman Team using another Superhuman’s Programmable Matter power to alter and bestow a fraction of their gift to them. This resulted in Linus’s body becoming Programmable Matter itself. Luckily, the proper authorities arrived to rescue him, but the kidnappers and Superhuman had escaped. Now, he is a Custodian and Groundskeeper for Vaughn’s University for Superhumans.