Willy Boy, Novice of Squash

First strike
At the beginning of your end step, put X racket counters on Willy Boy, Novice of Squash, where
X is the number of creatures that entered the battlefield or died this turn.
{2}{w}{p/g}: Create X 1/1 tennis ball tokens, where X
is the number of racket counters on Willy Boy,
Novice of Squash. If X is ten or more, instead
create that many 2/2 tennis ball tokens, then transform Willy Boy, Novice of Squash.