Goblin Cruciverbalist (UNF-110) [Unfinity]

Haste
When this creature enters, create a colorless artifact token named your choice of A, E, I, O, or U.
Whenever this creature attacks, using the first letters of the names of permanents you control, spell a word you haven't spelled this game. It gets +1/+0 until end of turn for each letter in that word.