Does Magma Wurm see itself (does its ability trigger when it enters the board)?

Ruling: No, Magma Wurm does not see itself because the card text specifies "other" friendly units.

Nuances:

• If the card said "friendly units enter ready" without "other," it would see itself because passive abilities become active before a unit enters the board exhausted
• The timing works this way: card text becomes active first, then the unit enters the board, so self-referencing enter effects can work if not restricted by "other"